The invention discloses an indoor air quality regulating and controlling system and method based on personnel location detection. The system comprises a data collection system, a computer system and an indoor environment regulating and controlling system. The data collection system comprises a personnel counter, an infrared array sensor and an air quality sensor module. The indoor environment regulating and controlling system comprises an indoor integrated main ventilation purifying system and a local regional space ventilation purifying system. The indoor integrated main ventilation purifyingsystem performs indoor integrated ventilation purifying according to the total number, transmitted to the computer system, of indoor persons. The local regional space ventilation purifying system determines whether the local regional space ventilation purifying system is started or not according to data which are transmitted to the computer system by the infrared array sensor and the air qualitysensor module. By means of the regulating and controlling system, the concentration of indoor environment pollutants and the running energy consumption can be controlled more reasonably, the whole airquality operation level can be improved, the risks to health of human bodies and the loss of working efficiency are reduced, and building energy saving is facilitated.