With the development of network and communication technology in modern society, WiFi technology has become an indispensable part of people’s lives. WiFi shows its future application prospects with its wireless portability and multi-user access. This paper briefly introduces the meaning and development of WiFi technology and predicts its future development trend. The communication modulation technology QPSK, 16QAM in WiFi is described in detail, and its characteristics are compared by systemview and MATLAB software. Finally, we summarize the common techniques in WiFi.