Navier-Stokes control equations and standard turbulence model are employed to numerically simulate the aerodynamic characteristics of forward-swept wing (FSW) and backward-swept wing (BSW). The superiorities and shortages are compared, and then the flow mechanism is analyzed by streamlines display. The research results show that the lift coefficient of BSW is higher in low angle of attack while the stall characteristics of FSW are better in big angle of attack owing to the opposite direction of the spanwise velocity. The premature wingtip stall induces lower angle of attack while stalling. The reason why FSW has better performances during big angle of attack is the favorable interference produced between vortices of side-strake and wingtip leading edge, which affords great vortex lift and enhances the control ability to the flow on the wing surface. The flow mechanism of the forward-swept wing can provide theoretical references for the design of the advanced aircraft configurations.