Based on the network complexity of formation communication topology， a minimum rigid formation communication topology generation algorithm is proposed for multi-agent system. First， the minimum rigid communication topology set of the agent formation is found by generating the minimum rigid communication topology based on the stiffness matrix. Second， the evaluation index of network complexity is established through reducing the collision probability between the members of the formation and reducing the communication consumption. The entropy weight method is used to solve the weight of each index. The calculation method of network complexity is given. Third，in the minimal rigid communication topology set， the formation communication topology with the minimum network complexity is found. Simulation results show that the algorithm can effectively reduce the complexity of formation communication topology and simplify the communication topology structure.