In view of the high ventilation negative pressure and stable operation of eastern shaft in Dongpan Mine, it was proposed to change the working wind resistance curve of main ventilation machine, to expand the roadway to renovate the local roadway and optimize the working condition of the main fan, based on the numerical values, derivation calculation settled the optimization and improvement of the main fan working conditions. The ventilation resistance of the eastern shaft can be reduced by 340 Pa, and the air volume of the system was increased by 1 300 m3/min, which could significantly improve the working conditions of the main fan. After the mine completed the renovation of the east wing of the air return roadway, the fan blade was adjusted to a maximum angle of 69°. At this time, the fan operating point was hC = 2 560 Pa, QC = 12 180 m3/min, the fan without unstable appearance. The actual verification showed that the measured ventilation parameters after the renovation were basically consistent with the theoretical calculation parameters, which proved the correctness of the numerical theory derivation.