In view of the imperfect air quality monitoring network and low level of monitoring refinement, an open air quality monitoring system is proposed. Integrating the advantages of small sensor air quality monitoring equipment and large air quality monitoring equipment, a large data intelligent cloud platform is constructed. Based on mobile location and data correlation, the automatic calibration of small sensor monitoring equipment is realized, and the zero drift problem of small sensor monitoring equipment is solved. An intelligent air quality prediction algorithm is proposed based on information fusion technology. It realizes the real-time control of the air quality of the specific location by ordinary users. The experimental results show that the system has low mean square error and high accuracy, and can effectively and automatically calibrate the monitoring equipment.