Abstract: In order to reveal the gas emission and migration laws of residual coal in the gob and coal wall above the support in the fully mechanized caving face with U+I-shape ventilation system, No.3205 fully mechanized caving face of Wangpo Coal Mine was taken as the site background, the steady computing model of gas emission and migration of residual coal in the gob and the unsteady computing model of gas emission and migration of the coal wall above the support were set up. Quantitative analysis was carried out on the influence of the face advancing speed, the thickness of the residual coal in the gob and the distributed air volume in the face on the gas-concentration field distribution formed by the gas emission of residual coal in the gob, and quantitative analysis was also carried out on the influence of the moving direction of support and top-coal caving direction on the gas-concentration field distribution in the gob and roadway formed by the gas emission of the coal wall above the support. The results have important guiding significance for gas overrun prediction in the coal face.