In order to study the mining pressure law of 4322 fully mechanized working face with large mining height in Chengzhuang Mine, the stress value of roof was calculated by numerical simulation software FLAC3D. The peak of front abutment pressure was 22.6 MPa, and the peak was about 15 m in front of working face. To effectively control the working face roof, according to the working status of the support, the working resistance provided by the support was calculated. When the support worked in the given deformation state, the roof subsidence was large and did not meet the requirements of safety production. When the support worked in the limited deformation state, the hydraulic support with a support resistance of 12 000 kN was needed. According to the mining process of the large mining height working face, the working procedures of the middle support and the end support were studied.