Abstract: In order to solve the problem that the ventilation was not reverse when the air was inverted in main air-intake roadway of Zhangji coal mine, the law of air pressure balance and the ventilation energy equation was used to analyze the ventilation system, and derive discriminant of the air disorder. The practical measured data was used to verifier the discriminant, and the results showed that it was correct.Combining the discriminant and the practical situation, the measure was provided to prevent the ventilation not reverse, to ensure stability of the mine ventilation system and improve its ability of fighting against disaster.