Spalart-Allmaras(SA) one-equation turbulence model has been prevailing used in the numerical simulation of engineering turbulence flows. In this paper, the flow situations of small incidence, middle incidence, large incidence of a typical fighter are concerned. And the influences of eight model parameters in SA turbulence model on the calculated turbulent flow fields are analyzed by using the uniform design of experiments. The results show that under different flow situations do the model parameters exhibit different influences on calculated results of lift and drag coefficients. For attached flow of small incidence, the influences of the parameters cv1 and cb1 are much greater than other parameters, and for middle incidence and large incidence, the parameter of largest influence is cb1. Then the turbulence model parameter estimation method is developed and utilized for the estimation of cb1 value for large incidence case. It is found that when the parameter value of cb1 decrease moderately, the calculated lift and drag coefficients agree with the experimental results much better. This could be attributed to that the conventional value of the model parameters are calibrated from free shear flow but there exists some difference in the development of eddy-vicosity and shear stress between the large incidence separated flow and the free shear flow.