Abstract: To achieve cooperative assembly for multi-robot in some station of an assembly line,taking the cycle time of an assembly line,the total energy consumption and the total cost of robots as the minimum optimizing objectives,a mathematical model with three objectives function was developed.To solve this problem,a multi-objective hybrid imperialist competitive algorithm (MOHICA) was proposed based on a three-level coding rule,i.e.the station level,the task level,and the robot level.In addition,a non-dominated sorted rule of genetic algorithm and a late-acceptance hill-climbing algorithm were combined into the algorithm to increase the exploration ability of the algorithm.Finally,simulation experiments and theory analysis were carried out to evaluate the proposed algorithm.The results indicate that the proposed algorithm is valid and feasible.