In order to solve the bus voltage high frequency oscillation problem caused by cascading constant power load and LC filter in marine DC microgrid, a suppression method for bus voltage oscillation based on virtual damping compensation of DC microgrid grid-connected converter was proposed. Firstly, the small signal model of source-side grid-connected converter and constant power load was established to analyze the mechanism of voltage oscillation caused by negative impedance characteristic of constant power load reducing LC filter damping, and the stable constraint conditions of cascade connection between LC filter and constant power load were derived. On this basis, a virtual negative inductance active damping compensate method based on nonlinear disturbance observer was introduced to estimate the output DC current of the grid-connected converter, and a virtual negative inductance compensation link was constructed to counteract the larger inductance value of the LC filter, thus suppressing the low damping oscillation of the system. Finally, the Nyquist criterion was used to analyze the stability of the cascade system, the effectiveness of the proposed control algorithm was verified by Simulink simulation model.