Abstract: In order to investigate the influence of approximate computation scheme for transport coefficients in gas mixtures on the numerical simulation of the flow field of scramjet combustor, the cold flow field with multicomponent gas mixtures in Burrows-Kurkov combustor has been simulated numerically by using the Favre-Averaged Navier-Stokes equations with the two-equation k-ω SST turbulence model. The effects of approximate computation scheme are studied for transport coefficients in gas mixtures on the numerical simulation with boundary layer and shear layer. The result indicates that:1) by comparing with direct computation scheme thermal conductivity coefficients and diffusion coefficients in gas mixtures calculated directly by approximate formula, the correlated calculation scheme, with those obtained by an algebraic formula consisting of Prandtl/Schmidt number and viscosity coefficient of the gas mixtures can produce comparative results and rapidly reduce the computation cost; 2) without the consideration of the consistence with the governing equation, the effect of computation schemes for diffusion coefficients in gas mixtures is insignificant; 3) in the numerical simulation of turbulent flow field, the turbulent transport coefficients in the boundary layer and shear layer are much greater than the molecular transport coefficients in gas mixtures, and the effect of different computation schemes for the molecular transport coefficients in gas mixtures is weakened consequently; 4) comparing with the computation==schemes for the molecular transport coefficients in gas mixtures, the compressible correction terms to Menter's two-equation turbulence models have greater effect on the composition profiles. The results also show that the approximate computation scheme for transport coefficients in gas mixtures plays an important role in the precisely numerical simulation for the boundary-layer flow fields near surface, shear-layer flow fields, and laminar flow fields with multicomponent gas mixtures.