Abstract: Experimental simulation method is used to research the coupling mechanism of influence factors such as atmospheric pressure, negative pressure of suction and ventilation negative pressure on gas emission in gob. The study discusses gas occurrence and emission instantaneous impact characteristics and laws under the influence of "three pressure". The test results show that gas emission concentration have a certain lag effect in contrast to large ground pressure, the average lag time is about 1 h, the ventilation rate working face increased from 990 to 1 071 m³/min, gas emission concentration increased by 4% compared with the initial, then declined to the initial value below.