Abstract: According to the stage back filling method in the southern district of Sijiaying, the feasibility and stope parameter optimization design research are made  Firstly,in the research area based on the engineering geological conditions，the recovery plan and the variation of parameters scope can be determined by engineering analogy and mining the preliminary design.Secondly，according to the parameter selection scope，the numerical model for orthogonal 16 group parameter combination of numerical analysis is established   Thirdly，according to different stope stability and rock movement parameters obtained by the numerical simulation，the function relation between the stope safety, strata movement parameters and design parameters is built by adopting the regression analysis.Fourthly，taking the economic benefit of plate area as optimizing targets of mining, the optimization model is established to realize optimization decision for southern stope structure with the stope stability and rock movement control parameters as constraint conditions  The comparison of this result indicated the stope mining of surface subsidence，the influence of stress and stability.Finally，the numerical analysis on the optimal design parameters is made to research and evaluate the surface subsidence，stope stability and economic benefit of the southern mining area in back  filling method.

Key words: Stage back filling method, Parameters optimization design, Orthogonal numerical test, Optimization analysis and evaluation