This paper first analyzes the logical relationship in mining system of fully mechanized coal face and then establishes the system reliability calculation model and simulation model. Based on the running technological data from the mechanized coal face, the authors obtain normal production service distribution and set up equation of monthly output and availability, with which the production and availability are simulated. The test of simulation results on actual condition shows that the simulation method is reliable. This approach contributes to performance evaluation on fully mechanized coal face, improvement on mining system, optimization of mining parameters, equipment modeling and matching. It can also be extended to reliability analysis of other systems.