Abstract: In order to solve the problem of increasing gas emission caused by ultra-high intensity mining in fully mechanized top coal caving face with large mining height, starting from the gas emission law of fully mechanized caving face with large mining height, the source of gas emission in working face is analyzed by branch prediction method, gas occurrence and flow field distribution are simulated by FLUENT software, the gas emission situation of working face is measured, and the gas drainage method is optimized. The control method of large flow gas in gas roadway is used to optimize the air flow route of working face, and change the path of gas emission from goaf to upper corner and goaf. The results show that: the special gas roadway closed large flow gas control method can reduce the total amount of gas emission from the working face to the mining space. During the drainage period, the gas concentration in the upper corner of 8103 working face is between 0.3% and 0.7%; the gas concentration in the return air roadway is below 0.4%; the gas concentration in the back chute of the support is reduced to less than 0.5%, which eliminates the gas overrun in the back chute during coal caving.