The supersonic flow (Ma=2.0) past several types of microramps is simulated by the numerical simulation method to improve the characteristics of isolator. The result follows that with the increase of the width at the trailing edge of MVGs, the length of the shock train becomes shorter, and the position of pressure leading edge moves backward. Meanwhile, the spanwise distance of streamwise vortices generated by entirety type MVGs is closer than that of the separated, but the distance to the bottom wall is farther. And the result also indicates that the momentum can be delivered to boundary layer in short distance to improve the flow condition. MVGs with wide back width can reduce total pressure skewness and is superior to the basic model.