Abstract: There are many intersections in preparatory workings of soft rock tunnel at Beiminghe Iron Mine,3D numerical simulation analysis of the intersection between link roadways based on software FLAC3D ,in which the mechanics of wall rock & displacement & deformational and destructive law are studied, and compared the results between simulation monitoring & practicality monitoring of control points. The results show that the numerical simulation methods must be supplemented by monitoring & measurement on-the-spot, so as to reflect the distribution and other features of rock stress &displacement& plastic zones objectively and correctly in the process of underground engineering, and providing effective reference for construction design.