Abstract: In order to further investigate the occurrence mechanism of blast disaster in coal mine, the influence of working face extraction on the regional stress field of surrounding rock at the haulage gateway of 13230 working face is analyzed by way of numerical simulation based on “12 ·22” rock burst accident of Gengcun Coal Mine,and the curves of principal stress are obtained along the axial direction of mining roadway. Due to the induction of external dis- turbances such as coal cutting,caving,first or periodic weighting of working face,front or side abutment pressure and so on,the biggest size of plastic zone is expanded by 2. 2-3. 4 times. Therefore,the occurrence mechanism of “12· 22” blast disaster in Gengcun Coal Mine is revealed. In the geological environment,because of the induction of trigge- ring event like external disturbances,the regional stress field of surrounding rock at the haulage gateway of 13230 working face will be suddenly changed,and a huge amount of elastic energy which is gathered in the body of coal will be suddenly released in the form of vibration,sound and coal or rock mass burst which stands for an explosive power and seriously destroys the 150 m mining roadway from the working face.