Abstract: As coal mine safety and production become more dependent on grid stability, it is increasingly important to accurately assess the safety level of coal mine power supply systems. General grid evaluation strategies often use the average state level to characterize the safety of the system, which ignores the influence of extreme individual components in the power grid on the entire system, so it cannot accurately describe the safety level of the coal mine power supply system. Combined with the actual operation characteristics of coal mine power grid, a reliability evaluation strategy based on expected fault information is proposed. This strategy evaluates the security level of the system by analyzing the comprehensive evaluation method of the system as a whole and individuals. At the same time, under the premise of weighing benefits and safety, two economic indicators of reliability cost and power outage loss cost are proposed, and the least squares algorithm is used to curve fit the historical data of the system, and the characteristic weight of system economy and safety and the relationship between system safety and economy are obtained, so as to obtain the optimal operation mode of the system. Finally, the feasibility of the proposed evaluation strategy is verified by practical examples.