In windows 2000 environment, the method of serial port communication development is summarized. Every method to program is introduced, and their advantages and disadvantages are compared. For application requirements, the appropriate development methods are selected. The serial port data processing and serial port module packaging are studied. The method of ring buffer data processing and the method that the serial port communication module is packaged using dynamic-link library (DLL) are introduced, and these methods are validated by the code of Visual C++.