In order to solve the problem of air volume demand after the transformation of Zhanghuagou partition ventilation system in No.1 Mine of Huayang Group, the technical transformation design of the existing main ventilators was carried out in this study. By calculating the existing return air capacity of the mine, the selection basis of the fan transformation is determined, and two transformation schemes are designed. The calculation and comparative analysis are carried out from the aspects of air volume, air pressure, efficiency and economy. The results show that it is more appropriate to select the long-axis axial flow fan with a fan diameter of 2 660 mm and a rated speed of 1 000 r/min. The scheme can meet the needs of mine ventilation, and the cost is low and the construction period is reasonable. The optimization design of fan transformation is realized.