Based on the mining practice of 8303 mining face with large mining height in Yangquan Mining Group No. 1 Mine, the roof caving mechanism and surrounding rock control technology of large mining height fully mechanized mining from the aspects of coal wall and roof leakage were studied by means of similar simulation, theoretical analysis and field observation. It was considered that it was difficult to form a stable occlusion structure between the roof above the support and the strata in the goaf, which increased the difficulty of the goaf support. The contact between support and roof changes from surface contact to line contact, the position of resultant force action point changes, and the support efficiency decreases, which made the working face vulnerable to leakage accident before the support. Some technical measures were put forward to control the surrounding rock, such as moving frame ahead, scraping frame with pressure, controlling the flatness of roof and floor, laying metal mesh on roof and pasting pillars, with guiding significance for safe mining on site.