The multi-microgrid system will have a great impact on the distribution network operation when connected with that. Aiming at this problem, based on the bilateral transaction mode under the market environment, this paper proposed a two-layer dispatching optimization model of active distribution system integrated with multi-microgrid. The lower layer of the optimization model was a decentralized synergetic scheduling for multi-microgrid and the primal-dual interior point method was used to solve locational margin price (LMP) of the multi-microgrid at common connection point (PCC). Meanwhile a decentralized cooperative scheduling strategy was designed to determine the exchange power between microgrids to realize the economic operation of multi-microgrid. The upper distribution system reconfiguration model was to optimize the grid loss to alleviate the operational risk brought by the multi-microgrid integration. The optimal operation scheme was obtained by binary particle swarm optimization （BPSO） algorithm. The safe and economic operation of distribution system integrated with multi-microgrid was realized through two layers of optimization. Finally, three interconnected micro-grids were embedded to the IEEE 33-node distribution system as an example to verify the effectiveness and rationality of the proposed scheduling method.