Abstract: Improving the recovery rate of top coal is the key of fully mechanized top coal caving mining technology, and the crushing degree of top coal and the caving after crushing have an important impact on the recovery rate of top coal.Therefore, it is of great significance to study the failure mechanism, fragmentation degree and caving law under different process parameters for realizing high yield and high efficiency of fully mechanized top coal caving face in thick coal seam.Based on the research background of 12309 fully mechanized top coal caving face in Wangjialing coal mine 2^# coal seam, through the combination of theoretical calculation and similar simulation experiment, the reasonable coal caving step is 0.865 m; on the basis of reasonable mechanical mining height and coal caving step, different coal caving methods are studied, and it is concluded that the most reasonable coal caving process is one mining and one caving; finally, based on the coal caving process parameters obtained from the research, the coal caving of 12309 fully mechanized top coal caving face in Wangjialing coal mine 2^# coal seam is numerically simulated.The top coal recovery and gangue content are 90.6% and 7.2% respectively.Considering the difficulty of on-site coal caving control and the production efficiency of the working face, it is determined that the reasonable coal caving mode is single round interval coal caving mode.