Abstract: In order to study the influence of multi-source and multi-load parameters on the stable operation of the system, a small-signal model of multi-source and multi-load DC microgrid is established in this paper. The voltage stability analysis is carried out based on the oscillation modes and participation factors of the system. The stability margin analysis of the system with the same kind of parameter coupling is carried out. When three power supply, a new pattern is discovered that the system stability margin is larger when the source-line length is “two long and one short” than when the source-line length is “two short and one long”. The interaction between the droop coefficient and the virtual inertia coefficient is explained in detail in the stability margin analysis under heterogeneous parameter. Based on the coupling interaction of multiple control parameters, the optimal design method of control parameters is proposed to achieve the maximum stability margin of the system and have the ability to provide greater inertia. Finally, the experimental results verify the correctness of the above analysis.