At present, the air quality detectors on the market can usually only detect a few kinds of gases. In the face of multiple harmful gases in the air, different detection instruments must be used. In response to the incomplete functions of the existing detection system, a multi-function detection system composed of STM32 MCU, various sensors, LCD display and WIFI communication module has been developed, and Gizwits is used to transmit data to the user terminal. The detection system can realize real-time monitoring of the content of CO, CO2, PM2.5, TVOC, formaldehyde, and temperature and humidity in the air, and has an alarm function for exceeding the standard.