Abstract: In order to solve the problems of insufficient total air volume,serious air leakage and unreasonable ventilation equipment selection and layout in Longqiao Iron Mine,the ventilation network models of main auxiliary fan and multi-stage fan station are established by using Ventsim three-dimensional visual air network solution software,and the fan selection of multi-stage fan station is optimized according to the solution results.The analysis of the air network calculation results show that:① When the total air volume of the main auxiliary fan ventilation system at full frequency (50 Hz) is 364.94 m3/s and the fan frequency of the multi-stage fan station ventilation system is 48 Hz,the total air volume of the system reaches the design air volume,but the total air volume of the multi-stage fan station ventilation system is surplus,which is better than the main auxiliary fan ventilation system.② The ventilation system of multi-level fan station is set with 4-level fan stations.Level Ⅰ is the main inlet fan station,level Ⅱ is the stope inlet fan station,level Ⅲ is the stope return fan station,and level Ⅳ is the main return fan station.The optimized level Ⅰ main inlet fan station adopts two k40-8-№ 23 fans in parallel,level Ⅲ return fan station adopts two k40-8-№ 21 fans in parallel in the East and two k40-8-№ 23 fans in parallel in the West.The scheme meets the air volume distribution requirements of -420 m middle section and -490 m middle section of the mine.