Abstract: In executing the order task of the mobile robot in the warehouse logistics, the dispatching system is difficult to perform task assignment quickly and accurately, and the handling route is not the shortest optimal route. According to the mobile robot’s movement mode and the requirement of order task, a reconfigurable warehouse space model and a grid map model are constructed, solving the shortest completion time allocation problem of order task by establishing a mathematical model, and improving the insufficiency of three common distance algorithms in traditional A^* algorithm, and a complex diagonal distance algorithm is proposed for path planning simulation. The simulation results show that the above method achieves the task assignment with the shortest task completion time, which reduces the number of path planning search nodes by 30% and the path length by 20%.