Abstract: For reducing the energy consumption and congestion of packet transmission in mobile ad hoc networks, it proposes an ant colony optimization routing protocol which takes into account energy balance and congestion control. The routing protocol is based on the AODV routing protocol, including two phases:route discovery and route maintenance. In the route discovery phase, the ant colony optimization algorithm is used to select the optimal nodes with maximum residual energy, minimum path cost and minimum delay variation for route construction. In the route maintenance phase, it monitors node's energy threshold level and path energy cost, to limit package transmission on the nodes or paths whose energy does not meet the conditions, for reducing energy consumption and improving life of network; and uses GPRS technology to quickly detect the link disconnection, for maintaining stability of route. The simulation results show that, this routing protocol requires less average hop count, high packet delivery rate and less end-to-end delay.