Abstract: The validity of the ant colony algorithm has been demonstrated as a powerful tool to solve the optimization problems. This technique is used to solve difficult combinatorial optimization problems but is seldom used for continuous space search due to its biological background. A nested hybrid ant colony algorithm is proposed in this paper to solve the complicated production scheduling problem with hybrid variable structures, and a rovel optimal path pheromone update algorithm is suggested to promote search efficiency. Computer simulation results show that the proposed method is more effective than genetic algorithms as a kind of evolutionary algorithms in solving such kind of difficult problems.