Abstract: In order to survey maximum allowable blade installation angle and maximum allowable revolving speed of main fans in coal mine, the performance test are carried out for two main fans in Qianjiaying Coal Mine under different blade angles and different revolving speed. The measured results show that the corresponding surge resistance is small when the blade angle is large and the revolving speed is high; that’s to say, the main fan will be easy to surge. The effect is not particularly clear to improve the fan ventilation capacity by changing the blade angle. For the same blade angle, the air volume and air pressure of fan is significantly improved with the revolving speed increasing.