In order to improve the recovery rate of top coal in the 0291 fully mechanized top coal caving face of Tangshan Coal Mine, the amount of top coal loss in the production process was theoretically calculated from seven aspects, namely, end loss, inter frame loss, and initial mining loss, using inter step loss as an optimization object, PFC2D software is selected to optimize the coal drawing step distance. According to the principle of "stopping when there is waste", the top coal drawing amount of different coal drawing steps is compared. The simulation results show that the top coal drawing amount exhibits significant fluctuations with the passage of the support. The step distance coal drawing amount of "one?cut?one?falling" is between 80-560 blocks, the step distance coal drawing amount of "two cut?one?falling" is between 50-680 blocks, and the step distance coal drawing amount of "three cut?one?falling" is between 100-1100 blocks, From the perspective of total coal discharge，the highest efficiency of coal discharge is "one?cut?one?falling", with a top coal discharge amount of 3832 pieces. Therefore, when the coal discharge step is optimized to "one?cut?one?falling", the loss between coal discharge steps can be effectively reduced.