Based on the computational fluid dynamics module CFX of ANSYS 11.0,RANS 3-D Navier-Stokes equation and SST model are selected. And the numerical method of N-S equation and visual flow-field simulation analysis are used to calculate the aerodynamic characteristics and flow mechanism of the configuration with variable forward swept and orthogonal wing in the stage of low speed taking-off/landing together with high transonic combat utilization. The comparison of the two configurations above is emphasized. The analysis of vortex configuration has shown that the wing leading edge vortex and canard vortex get closer and are enhanced each other in 'V' shape, thus the secondary vortex is induced which greatly raises the control ability of the flow separation upon the wing, so the lift coefficient and stall angle are increased. The numerical results and analysis have proved the rationality of the guiding ideology and can provide theoretical supports to the advanced nature of the aircraft design with the configuration of variable swept wing.