To solve the cargo arrangement problem of multiple picking stations in multi-module grid-based storage system, a decoupled decentralized control method is proposed, which decouples the problem into independent scheduling of each module and cooperative scheduling between modules. The cycle movement method is used for independent scheduling within the module, and the cooperative scheduling is realized by exchange requirements and module states. Simulation is carried out under different parameters, and a comparative simulation with centralized control method is carried. The results show that the decentralized control method can get solutions stably and effectively under various conditions, and can get better solutions and shorter computing time than the centralized control method. The effectiveness and universality of the proposed method are verified.