In off-design conditions the corner separation can become severe thus lead to strong non-equilibrium turbulent state.To correctly simulate the flow field the transport process of non-equilibrium trubulence must be predicted reasonable.Based on the analysis of turbulence transport nature at different operating conditions in compressor corner separation flows

a modification method on the relationship between the production and dissipation of turbulence viscosity to improve the simulation ability of Spalart-Allmaras(S-A) model at off-design condition in compressor flow was proposed and studied by numerical simulation.It shows that comparing with experimental data and academic analysis the modified S-A model could give out more reasonable and correct predictions than conventional S-A model.