For the multi-constrained routing problem, there are several constrained parameters such as the bandwidth, delay, packet loss rate, delay jitter, the QoS parameters influence each other. It has been proved as a NP-Complete problem, traditional linear method often have some difficulties in solving this problem. The application of ant colony algorithm or genetic algorithm often has a slow convergence speed and might fall into the local optimal point. This paper introduces a hybrid algorithm (Genetic-Ant Colony Algorithm) which can reach the global optimum within a short time.