A 3d LU-SGS computational code was developed to solve the hypersonic flows, which was modeled by using the compressible three-dimension Reynold averaged Navier-Stokes equations and a finite volume formulation, the convective parts were discretized with the Harten TVD scheme, and the turbulence effect was modeled utilizing Menter SST two equation turbulence model. The flowfield of 18×18 degree fins generated crossing shock wave/turbulent boundary layer interactions were studied at Mach 4.96, a 3D separated flowfield was analyzed and the numerical results were compared with experimental and numerical results from references.