Abstract: In order to have the seam gas deposit law of Dongzhouyao Mine and to provide the basic data for the mine gas control, the paper introduced the geologi cal structure features and seam conditions of Dongzhouyao Mine . According to the seam depth, the geological report, the neighbour mines and the measured gas conte nt and component in the underground mine, the paper had a study on the gas deposit law of the No.5 seam in Dongzhouyao Mine.The study showed that No.5 seam in Dongzhouyao Mine would all be in a gas weathered zone .From the view of the coal metamorphic grade, the roof and floor features and the geological structure, the pap er analyzed the cause of No.5 seam in gas weathered zone. The paper held that the metamorphic grade of No.5 seam was low and the gas quantity from the coal format ion period was low.Due to the Tertiary System strata were varied thin, great gas were released.There was tension structures existed in the minefield and those structure s could provide the channel for the gas migration to the surface ground.All above would be the main causes to make No.5 seam in the gas weathered zone in Dongzhou yao Mine.