In order to solve the problem of excessive energy consumption for transmitting to sink node directly from cluster heads in LEACH routing protocol, a routing protocol based improved ant colony algorithm was proposed. This protocol introduced leadSthe energy consumption factor to improve the ant transition probability and the pheromone updating rule. And It would take full account of the residual energy of nodes and the distance between the nodes, through the establishment and update of pheromone, make sure to find the optimal path between cluster heads and base station, and use multi-hop transmission to balance the energy consumption of cluster nodes. Simulation results show that this improved routing protocol better than LEACH protocol on the cluster-head nodes selection, and it can extend the survival time of the network, and makes the energy consumption more balanced.