The invention discloses a mobile energy storage contained micro-grid expansion planning method. A pre-established grid-connected AC micro-grid topology model is expanded into a mobile energy storage contained grid-connected AC-DC mixed micro-grid topology model; an optimization target, optimization constraint in normal condition and a scheduling strategy of mobile energy storage when a DC/AC converter faults causes splitting of an AC-DC mixed micro-grid system, an optimization constraint under the fault condition is determined according to the scheduling strategy, and a mathematical model of mobile energy storage capacity optimized configuration in the mobile energy storage contained grid-connected AC-DC mixed micro-grid is established; and the model is solved according to the optimizationtarget and optimization constraint to obtain a mobile energy storage capacity optimized configuration result of the mobile energy storage contained grid-connected AC-DC mixed micro-grid. The problemthat micro-grid expansion planning wastes resources can be solved, the condition that energy in the two sides during AC/DC side splitting operation is not circulated can be alleviated, the expansion planning cost of the micro grid is reduced, and the micro grid system is more economical.