Visual Basic statements are not thread-safe and are not suitable for multi-threaded work patterns. There are about 4 mechanisms for implementing multithreading under Visual Basic: Win32 API, ActiveX DLL, ActiveX EXE, and third-party thread library Thread Factory. According to different application requirements, different mechanisms can be used to develop Visual Basic multi-threaded applications, so as to better play the characteristics of VB's high efficiency, rapidity, and powerful interface design.