Abstract: DC microgrids often contain constant power loads (abbr. CPLs), whose negative impedance characteristics can reduce the stability of the system, causing DC bus voltages to fluctuate and even collapse. Therefore, firstly, a small-signal model of DC microgrid is established, and the influence of constant power load on system stability is analyzed using the root trajectory method; secondly, a hybrid sensitivity optimization-based voltage control strategy is proposed to improve the stability of the DC microgrid system, and an improved particle swarm optimization(abbr. PSO) algorithm is used to optimize the weight function and further improve the performance of the robust controller; finally, a Matlab/Simulnik simulation is used to verify the performance of the robust controller, and the simulation results show that the proposed robust controller reduces the bus voltage fluctuation and effectively improves the stability of the DC microgrid system.