Abstract: A method of three-dimensional numerical simulation for the transonic turbomachinery rotor internal flow field by solving three-dimensional unsteady compressible thin-layer Navier-Stokes equations in rotating frame using finite volume method and Baldwin-Lomax algebraic turbulent model is presented.The local time step was used to accelerate the iteration process.Implicit treatment of convective fluxes was combined with the explicit treatment of diffusive fluxes.Roe’s method with three-order TVD scheme was used for the evaluation of convective fluxes,and central difference scheme was used for diffusive fluxes.Newton’s sub-iterations were applied to reduce the non-linear equations of conservative variable into linear one.The linear equations were solved using symmetric Gauss-Seidle iterative method.The case used for examining was NASA Rotor 67.Calculated performance,relative Mach number contours at different span location,spanwise total pressure and temperature distribution at rotor exit,etc.,were compared with the experimental data.Computation results agree well with experimental data at peak efficient point,but there is a little discrepancy at near stall point.