Abstract: In view of the concept confusion in the performance test method of coal mine ventilating fan, this paper adopts the method of combining theory and practice. Firstly, the relationship between the relative static pressure、relative total pressure at the entrance of ventilator and the total resistance of mine shaft ventilation is analyzed in theory. And it points out the error prone place when reading the data in the field performance test. Then it analyzes the misunderstanding of static pressure of device and total pressure of device for a long time, and points out the seriousness of the problem through a real field performance test case recently. Finally, it puts forward its own suggestions to relevant units and practitioners.