Maintaining DC bus voltage stability is a prerequisite for efficient, safe and stable operation of DC power grid. Multiple Voltage Source Converters (VSCs) integrates into DC grid with voltage droop approach. Voltage droop approach is equivalent to install a virtual resistor in series to VSC’s DC port. In general, droop approach realizes the power sharing between VSCs and improves the damping of DC system. However, research finds that when VSC is running with DC voltage droop approach, there is a negative resistance component in the output impedance of the VSC. The DC-side voltage is easy to produce high-frequency oscillations, because of the negative resistance, the line parameters and the complex impedance interactions by Constant Power Load (CPL). For this issue, small-signal impedance-based model of the DC power system is modelled and the stability of the DC system is analyzed in this paper. Next, a virtual capacitive resistance impedance control approach is proposed to reshape the output impedance of the VSC, the proposed approach keeps the positive impedance outside the bandwidth of voltage loop and it can suppress the oscillations of the DC grid. Meanwhile, the proposed approach improves the capacitive component of the output impedance of VSC; hence, the dynamic response of the DC bus is smoothed and the inertia of the system can be improved. Finally, simulation results validate the correctness and efficiency of this proposed control approach. This work is supported by Science and Technology Project of State Grid Corporation of China (No. 5455ZS170025) "Research on Inertial Control Method and Port Stability of Power Electronic Converter Connected to DC Power Grid".