Abstract: In the stability analysis of DC microgrid, a crisscross optimization algorithm(CSO) is proposed to solve the problem of improving system stability by multi-index optimization operation. CSO algorithm can realize global parallel search and effectively avoid the influence of parameter local solution on stability analysis. In this paper, a small signal model of multi-source and multi-load DC microgrid is established. The dominant mode of the system is calculated by eigenvalue analysis. The influence degree of state variables on dominant modes is decoupled by the participation factor method. The real part of the dominant mode is taken as the objective function of CSO, and the penalty function with conditional constraints is introduced to analyze the stability. The optimal solution of power supply droop coefficient is found through the search and optimization ability of CSO, so as to increase the damping and improve the stability of the system. By using CSO, it is found that the system stability can also be improved by using two-long-and-one-short transmission line at the source-side. Finally, the effectiveness and correctness of the proposed control strategy are verified by simulation analysis and experiments.