Abstract: In order to research the influence of self-adsobed water on gas desorption in coal, the spontaneous imbibition was realized by self-designed experimental device, the replacement effect of water for gas was researched alone, the amount of gas replacement desorption, the relief-pressure desorption and the residual gas in different water content were measured. The results indicated that the moisture could promote the replacement desorption of absorbed gas, the amount of replacement desorption increased with water content. In the process of desorption after gas pressure-relief, the gas desorption amount of moist coal was less than that of the dry coal during the same time, and decreased with increase of water content, residual gas content of moist coal was also less than that of dry coal after sufficient desorption, in water content range of 4%~10%, residual gas content decreased with increase of water content.For Yonghong anthracite in Jinchengg, self-adsorbed water content manifests overally acceleration effect for gas desorption. The influence of moisture on gas desorption is the combined influence of replacement effect and water-locking effect.