Abstract: For the problem of frequent accidents of crushing supports at 5210 fully mechanized caving face in advancing process of Shanxi province Wujiagou colliery. Based on working face roof falling and spalling statistics, online support load monitoring, combined with the geological conditions and surface morphology of roof and floor, we analyze the stability of the head face and coal wall, the setting load, support efficiency, overlying rock compound breakage, surface morphology and other factors. Besides, according to whether it can be adjusted artificially, dividing it into controllable and uncontrollable factors, and we proposed prevention measures for crushing supports effectively based on the principle of optimizing the controllable factors and weakening the uncontrollable factors.