Aiming at the problems of tunnel ventilation system, such as single control means, lagging control, low efficiency, and poor effect, a new method for comprehensive treatment of multiple harmful gases based on fuzzy theory is improved, and a comprehensive treatment system is constructed using fuzzy proportional integral derivative control technology. By using realtime monitoring data of sampling module, the system uploads the signal to the analysis module for global control. The fuzzy control module corrects parameters online, controls the frequency converter to improve the operating frequency of the controlled object continuously and circularly, and adjusts the air volume and the absorption liquid spray amount. Finally, ventilation dilution and spray purification are carried out by the treatment module to dispose various harmful gases. This system has been applied to a coal tunnel in Qinghai Province. The results show that the system can quickly reduce the concentration of gas and hydrogen sulfide at the monitoring section after blasting, and the average concentration values are reduced by 17.3%, 27.3% respectively at the excavation workface, 12.2% and 36.7% at the frontend of the lining, with high accuracy. After blasting, the time for the concentration to drop to the standard limit is also reduced from 20 min to 10 min on average, which is shortened by about 1~2 times. It effectively ensures the safety of tunnel construction and improves the efficiency of tunnel construction.