Abstract: The stability and transition of swept wing boundary layers have important reference value to the design and optimization of airfoil. The cross-flow instability is one of the key parameters for boundary layer transition. Based on the NLF(2)-0415 airfoil profile, the mean flow of the swept-wing boundary layer was calculated by numerically solving the three-dimensional compressible Navier-Stocks equation with γ-Re_θt transition model. Considering the original transition model could only predict the transition along streamwise, cross-flow intermittency factor was established to the original transition model to conduct the numerical simulation of cross-flow instabilities transition for complex configuration. The numerical results show that the improved transition model could predict the location of cross-flow instability transition of swept wing which is in good agreement with the test data. Therefore, improved transition model is reasonable and practical.