This paper proposes an ant-based routing al-gorithm with multi-phase pheromone and power-saving (ARMPP) for enhancing the adaptability and stability of mobile ad hoc networks (MANETs). The routing algorithmis based on the ant colony optimization framework that is a kind of swarm intelligence and inspired from the ant’slife. MANETs are dynamic, self-built and infrastructure-less networks. In MANETs, a link disruption resulting from the dynamic topology deteriorates the performance of network,and the increment of energy consumption brings reduction of the network lifetime because almost all nodes operate on abattery. The goal of this paper is to enhance the adaptability and stability in reacting to the mobility of nodes, that is,to variate the network topology timely and to maximize the lifetime of the network. We propose a two-stage construction method of pheromone and a new pheromone update method.In simulation experiments, we compare ARMPP with refer-ence algorithms such as ad hoc on-demand distance vector (AODV) and destination-sequenced distance vector routing(DSDV). The simulation results show that our algorithm can achieve better performance than those algorithms in the measures of the adaptability and stability.