Abstract: In order to study the method of stability analysis and parameter optimization of stope，several kinds of indexes representing the engineering quality of rock mass in mines were acquired by the survey of engineering geology，the ore-bearing rock mechanics experiments，digital testing etc in Xiadian gold mine.The quality of rock mass is briefly evaluated，including the quality of the 54903 stope is good，and the 55002 stope is normal.According to the acquired index，the stability of stope under the current span was analyzed using the Mathews stability graph method.In the current 6 m stope span，the span can be reasonably increased since the stability of stope is higher.The stope stability critical span was concluded by the formula of the fitting-damage curve.Then through the comprehensive consideration of many factors，the initial span is designed as 7 m.Based on the graph of soft rock critical span，it is evaluated that the initial span 7 m is economical and safe.The application accuracy of the diagram method is briefly discussed by using FLAC3D and the stope span is finally determined.

Key words: Mathews stability graph, Stability of stope, Parameter optimization, Graph of critical span, Numerical simulation