Abstract: Considering the ponderomotive force, the high-power microwave propagation in waveguide filled with plasma is analyzed and simulated. The propagation characteristics of the high-power microwave and the relationship between the power of the microwave and the distribution of the plasma density are researched. The results show that the ponderomotive force of high-power microwave would affect the dispersion, make the distribution of microwave different from Bessel distribution, and drive the plasma to the region where the microwave field is lower. When the microwave filed is sufficiently large, the low plasma density channel would form in the axial region.