diff --git a/.config.in b/.config.in
index f9ecec3fe..a10763202 100644
--- a/.config.in
+++ b/.config.in
@@ -2,6 +2,7 @@
 #define CONFIG_H_IN
 
 #define PROJECT_PATH "@CMAKE_CURRENT_SOURCE_DIR@"
+#define BUILD_TYPE "@CMAKE_BUILD_TYPE@-build"
 #define EXTAPI_DIR PROJECT_PATH "/@CMAKE_BUILD_TYPE@-build/svf-llvm"
 
 #endif
diff --git a/svf/include/Util/ExtAPI.h b/svf/include/Util/ExtAPI.h
index 2692dab1f..a5f0ec90a 100644
--- a/svf/include/Util/ExtAPI.h
+++ b/svf/include/Util/ExtAPI.h
@@ -38,7 +38,7 @@
 
 /// For a more detailed explanation of how External APIs are handled in SVF, please refer to the SVF Wiki: https://github.com/SVF-tools/SVF/wiki/Handling-External-APIs-with-extapi.c
 
-#define EXTAPI_BC_PATH "Release-build/svf-llvm/extapi.bc"
+#define DEFUALT_EXTAPI_BC_PATH "/svf-llvm/extapi.bc" // Default path to extapi.bc through the SVF build method(e.g. source ./build.sh)
 
 namespace SVF
 {
@@ -49,6 +49,9 @@ class ExtAPI
 
     static ExtAPI *extOp;
 
+    // extapi.bc file path
+    static std::string extBcPath;
+
     ExtAPI() = default;
 
 public:
@@ -57,6 +60,9 @@ class ExtAPI
 
     static void destory();
 
+    // Set extapi.bc file path
+    static void setExtBcPath(const std::string& path);
+
     // Get extapi.bc file path
     std::string getExtBcPath();
 
diff --git a/svf/include/Util/Options.h b/svf/include/Util/Options.h
index d911bb0b4..d52a1793d 100644
--- a/svf/include/Util/Options.h
+++ b/svf/include/Util/Options.h
@@ -248,6 +248,7 @@ class Options
     static const Option<bool> VtableInSVFIR;
 
     // WPAPass.cpp
+    static const Option<std::string> ExtAPIPath;
     static const Option<bool> AnderSVFG;
     static const Option<bool> SABERFULLSVFG;
     static const Option<bool> PrintAliases;
diff --git a/svf/lib/Util/ExtAPI.cpp b/svf/lib/Util/ExtAPI.cpp
index f919fd94d..22dbe0689 100644
--- a/svf/lib/Util/ExtAPI.cpp
+++ b/svf/lib/Util/ExtAPI.cpp
@@ -29,11 +29,13 @@
 
 #include "Util/ExtAPI.h"
 #include "Util/SVFUtil.h"
+#include "Util/Options.h"
 #include <sys/stat.h>
 
 using namespace SVF;
 
 ExtAPI* ExtAPI::extOp = nullptr;
+std::string ExtAPI::extBcPath = "";
 
 ExtAPI* ExtAPI::getExtAPI()
 {
@@ -53,6 +55,12 @@ void ExtAPI::destory()
     }
 }
 
+// Set extapi.bc file path
+void ExtAPI::setExtBcPath(const std::string& path)
+{
+    extBcPath = path;
+}
+
 // Get environment variables $SVF_DIR and "npm root" through popen() method
 static std::string GetStdoutFromCommand(const std::string& command)
 {
@@ -80,55 +88,77 @@ static std::string GetStdoutFromCommand(const std::string& command)
 // Get extapi.bc file path in npm
 static std::string getFilePath(const std::string& path)
 {
-    std::string bcFilePath = GetStdoutFromCommand(path);
-    if (path.compare("npm root") == 0)
+    std::string bcFilePath = "";
+    if (path.compare("SVF_DIR") == 0)
     {
-        int os_flag = 1;
+        bcFilePath = getenv("SVF_DIR");
+    }
+    else if (path.compare("npm root") == 0)
+    {
+        bcFilePath = GetStdoutFromCommand(path);
         // SVF installed via npm needs to determine the type of operating
         // system, otherwise the extapi.bc path may not be found.
 #ifdef linux
         // Linux os
-        os_flag = 0;
         bcFilePath.append("/svf-lib/SVF-linux");
-#endif
+#else
         // Mac os
-        if (os_flag == 1)
-        {
-            bcFilePath.append("/svf-lib/SVF-osx");
-        }
+        bcFilePath.append("/svf-lib/SVF-osx");
+#endif
     }
 
-    if (bcFilePath.back() != '/')
+    if (!bcFilePath.empty() && bcFilePath.back() != '/')
         bcFilePath.push_back('/');
-    bcFilePath.append(EXTAPI_BC_PATH);
+    bcFilePath.append(BUILD_TYPE).append(DEFUALT_EXTAPI_BC_PATH);
     return bcFilePath;
 }
 
 // Get extapi.bc path
 std::string ExtAPI::getExtBcPath()
 {
-    struct stat statbuf;
-    std::string bcFilePath = std::string(EXTAPI_DIR) + "/extapi.bc";
-    if (!stat(bcFilePath.c_str(), &statbuf))
-        return bcFilePath;
-
-    bcFilePath = getFilePath("echo $SVF_DIR");
-    if (!stat(bcFilePath.c_str(), &statbuf))
-        return bcFilePath;
+    // Five default ways to get extapi.bc path
+    // 1. Set extapi.bc path through setExtBcPath() method
+    // 2. Set extapi.bc path through the "-extapi = PATH_TO_EXTAPIFILE" option
+    // 3. Default path: "SVF_IR_PATH/CMAKE_BUILD_TYPE-build/svf-llvm/extapi.bc"
+    // 4. From $SVF_DIR
+    // 5. From "npm root"(If SVF is installed via npm)
 
-    bcFilePath = getFilePath("npm root");
-    if (!stat(bcFilePath.c_str(), &statbuf))
-        return bcFilePath;
-
-    SVFUtil::errs() << "No extapi.bc found at " << bcFilePath << " for getExtAPI(); The default path for extapi.bc is: SVF_IR_PATH/CMAKE_BUILD_TYPE-build/svf-llvm/extapi.bc !\n";
+    struct stat statbuf;
+    // 1. Set extapi.bc path through setExtBcPath() method
+    if (!extBcPath.empty() && !stat(extBcPath.c_str(), &statbuf))
+        return extBcPath;
+
+    // 2. Set extapi.bc path through the "-extapi = PATH_TO_EXTAPIFILE" option
+    extBcPath = Options::ExtAPIPath();
+    if (!extBcPath.empty() && !stat(extBcPath.c_str(), &statbuf))
+        return extBcPath;
+
+    // 3. Default path: "SVF_IR_PATH/CMAKE_BUILD_TYPE-build/svf-llvm/extapi.bc"
+    extBcPath = std::string(EXTAPI_DIR) + "/extapi.bc";
+    if (!stat(extBcPath.c_str(), &statbuf))
+        return extBcPath;
+
+    // 4. From $SVF_DIR
+    extBcPath = getFilePath("SVF_DIR");
+    if (!stat(extBcPath.c_str(), &statbuf))
+        return extBcPath;
+
+    // 5. From "npm root"(If SVF is installed via npm)
+    extBcPath = getFilePath("npm root");
+    if (!stat(extBcPath.c_str(), &statbuf))
+        return extBcPath;
+
+    SVFUtil::errs() << "No extapi.bc found at " << extBcPath << " in getExtBcPath() !!!" << "\n" 
+                    << "You can specify extapi.bc path in two ways:" << "\n" 
+                    << "1. Set it via the command line using -extapi=/path_to_extapi;" << "\n" 
+                    << "2. Use the API setExtBcPath(). Please note that setExtBcPath() should be used before buildSVFModule().\n";
     abort();
 }
 
 std::string ExtAPI::getExtFuncAnnotation(const SVFFunction* fun, const std::string& funcAnnotation)
 {
     assert(fun && "Null SVFFunction* pointer");
-    const std::vector<std::string>& annotations = fun->getAnnotations();
-    for (const std::string& annotation : annotations)
+    for (const std::string& annotation : fun->getAnnotations())
         if (annotation.find(funcAnnotation) != std::string::npos)
             return annotation;
     return "";
@@ -137,8 +167,7 @@ std::string ExtAPI::getExtFuncAnnotation(const SVFFunction* fun, const std::stri
 bool ExtAPI::hasExtFuncAnnotation(const SVFFunction* fun, const std::string& funcAnnotation)
 {
     assert(fun && "Null SVFFunction* pointer");
-    const std::vector<std::string>& annotations = fun->getAnnotations();
-    for (const std::string& annotation : annotations)
+    for (const std::string& annotation : fun->getAnnotations())
         if (annotation.find(funcAnnotation) != std::string::npos)
             return true;
     return false;
@@ -168,8 +197,7 @@ bool ExtAPI::is_arg_alloc(const SVFFunction* F)
 // Get the position of argument which holds the new object
 s32_t ExtAPI::get_alloc_arg_pos(const SVFFunction* F)
 {
-    std::string s = "ALLOC_ARG";
-    std::string allocArg = getExtFuncAnnotation(F, s);
+    std::string allocArg = getExtFuncAnnotation(F, "ALLOC_ARG");
     assert(!allocArg.empty() && "Not an alloc call via argument or incorrect extern function annotation!");
 
     std::string number;
diff --git a/svf/lib/Util/Options.cpp b/svf/lib/Util/Options.cpp
index 685ea8744..a8deae843 100644
--- a/svf/lib/Util/Options.cpp
+++ b/svf/lib/Util/Options.cpp
@@ -770,6 +770,13 @@ const Option<bool> Options::VtableInSVFIR(
     false
 );
 
+//WPAPass.cpp
+const Option<std::string> Options::ExtAPIPath(
+    "extapi", 
+    "External API extapi.bc", 
+    ""
+);
+
 const Option<bool> Options::AnderSVFG(
     "svfg",
     "Generate SVFG after Andersen's Analysis",