Abstract: A novel routing algorithm of wireless sensor network (WSN) based on ant colony optimization (ACO) is proposed. According to the routing strategy of WSN and the characteristic of ACO, the artificial ant and the framework of routing algorithm based on ACO were designed. The theoretical analysis of convergence of proposed algorithm was given and the simulation experiment in NS environment was done. The simulation result show that, in comparison with SPIN, DD, HREEMR, SAR and GEAR, the proposed algorithm has good energy saving and global optimizing ability.