Combined with the example of a coal mineparameter level of physical and mechanical of rock mass in parameter selection scope was obtaineddesigned orthogonal test table on this basis.Geometric model was based on roadway boundary conditionsthen got the displacement to establish PSO-BP neural network relevant study sample through finite element methodback analysis of displacement for prediction on rock physical and mechanical parameters model was obtained.The calculated result shows that the maximum error between the measured value and calculated displacement value by forecasting parameters is 3.27%.It is credible that physical and mechanical rock parameters can be obtained by means of inverse seeking displacementso it appears that the PSO-BP network is feasible in mine roadway displacement back analysis.