For solving the problem of finding suitable robot configurations to meet the specific tasks in the application of reconfigurable modular robot, a task-oriented multi-objective configuration optimization method is discussed. At beginning, the basic structure of the modular robot system is introduced, including the main modules and components of the control system. Then, based on the description of the task, an optimization model of modular robot configuration design is represented. Finally, for the specific tasks of climbing and manipulating, the configuration optimal design of modular robot is processed. The feasibility and effectiveness of the method have been well verified by the optimization simulation. The method is task-oriented and multi-objective, and it includes the performance optimization of degrees-of-freedom, reach-ability, energy consumption, and so on.