Abstract: in order to effectively sove the low drainage negative pressure in the driling borehole,the low flow of the drainage pipeline,the pipeline air leakage and other problems occurred in the network drainage process of the mine gas drainage system in Xiagou Mine,the optimization was conducted on the drainage system with the simulation nethod of the gas drainage system and the mine ventilation network features diagramBased on the pipe flow parameter calculation of the drainage pipeline,the MATLAB software and Cross algorithm were applied to solve the gas drainage system and the ventilation network feature diagram of the drainage system was obtained.Based on the analysis on the " five lines" features of the ventilation network feature diagram,the optimized measures to reduce the resistance were provided.The result showed that the total average mixed drainage volume at the drilling site was 0.1491 m~3/s and the mixed drainage volume at the top cormner was 0.262 2 m~3/s.The venilation network feature diagram of the gas drainage pipeline was in a triangle type distribution,the drainage flow was decayed in a linear with thepipeline expanded,and the analysis on the ventilation network diagram of the gas drainage system could directly show the resistance disributionso as to set up the optimized measures.