Abstract: Because of the complexity of the residual orebody space form,the traditional cutting drawing method is difficult to show the orebody form intuitively and comprehensively,leading to difficulties in cutting engineering design,while SURPAC uses a 3D modeling method to solve this problem. An induced caving method of residual orebodies was investigated with Xishimen Iron Mine as the background. The trench's ore quantity,metal quantity and grade were calculated by SURPAC. The horizontal and vertical positions of a trench tunnel were taken as the optimization objects,and the trench tunnel in both directions was laid out by analyzing the critical caving span and the field engineering and technical conditions. According to the scope,a scheme of orthogonal test was designed.Taking extraction metal quantity and average grade as the assessment indexes,the range analysis and variance analysis of orthogonal test were conducted to obtain the position of a trench tunnel: double trench tunnels have a separation distance of 24 m,with a horizontal level of 118 m. Along with the scene implement,ideal test results have been achieved for refinement caving.