Abstract: In this article, combining with top-coal arching, not easy to release problem at 14101 fully-mechanized caving face of Majialiang Mine of Datong Coal Mine Group, the arching mechanical model and the arching mechanism of the top-coal is established and analyzed, PFC numerical simulation software is use to analyze the state of several kinds of arching in the process of caving coal, to simulate the arch control and destruction of top-coal technology, learned that the top-coal bearing capacity of arch and slip resistance shear failure is arch damage occurred in two ways. After tail beam swing and tail beam previous swing then back swing can achieve the purpose of breaking the arch. Finally, the process approach of the working face is optimized and test, the top-coal recovery rate and production efficiency has been significantly improved, good results have been achieved.