Abstract: In view of problems that equivalent orifice commonly used in current mine ventilation difficulty degree evaluation cannot effectively reflect details of ventilation difficulty degree, and ventilation resistance measurement cannot well measure effect of complex ventilation system in parallel, an refinement analysis method of mine ventilation difficulty degree based on ventilation equivalent area is proposed. According to obtained roadway ventilation information, the ventilation system network is solved to obtain wind pressure of each node in the system, and the ventilation system is segmented according to the wind pressure of each node. The roadways in each section are in parallel. According to characteristics of equivalent orifice, the equivalent orifice of each section are first calculated to obtain the equivalent area of each section comprehensively, so as to obtain corresponding ventilation equivalent area of each node. In order to visually and clearly express difficulty degree of ventilation in each section of the ventilation system, the ventilation equivalent area is represented graphically, including the wind pressure-equivalent area diagram, node-equivalent area diagram, wind pressure-equivalent energy consumption diagram and node-equivalent energy consumption diagram. According to the ventilation equivalent area diagrams, the mine ventilation difficulty degree is analyzed in detail including wind bottleneck, resistance distribution and ventilation energy consumption. The results of example validation show that the method can effectively distinguish resistance area and local resistance position and ventilation bottleneck location in the ventilation system, and it can be used for analysis and optimization of mine ventilation.