The invention discloses an air quality detection and control system, which comprises a control panel and an air quality sensing device, wherein the control panel is provided with a key circuit, a second master control chip and a communication circuit; the output end of the key circuit is connected with the first input end of the second master control chip; the second master control chip is in bidirectional connection with the communication circuit which is in two-phase connection with the air quality sensing device; and the output end of the air quality sensing device outputs a control signal to control the running of a draught fan. The system has the advantages of automatically updating a reference value of air quality so as to improve the detection sensitivity to indoor air pollution, and saving energy because a three-stage timing function and upper and lower output limits of the draught fan are set to intelligently control the running power of the draught fan to regularly and quantitatively supply and exhaust air.