Abstract: Combined with occurrence characteristics of coal in Wu Lan mine, Mechanical model is established，and the mining adit and coal pillar width of the mining adit are theoretical analysis calculated. The characteristics of surrounding rock in each stage of mining and filling are calculated by numerical simulation. According to the analysis and calculation results, the working slope fill mining technology is successfully applied in Wu Lan coal mine. Stability of side wall is guaranteed, at the same time, the recovery rate of coal is improved greatly.