Abstract: In order to insure the safety of coal mining under building structure,railway and water body,we establish the corresponding mechanical model and calculate the reasonable coal-pillar width of the short-wall mining in this article;Then the short-wall mining process with the different coal-pillar width is simulated by RFPA2D.The influence to the coal floor and the overlying rock with different coal-pillar width is analyzed and compared;this process reproduces the destruction mechanism and moving rule of the mining rock.By comparing with the result of theory analysis and numerical simulation,we confirm the appropriate coal-pillar width and offer the basic basis to realizing laneway protection,resource sustainable utilization and economic sustainable development.