Wireless ad hoc networks becomes a new type of wireless networks gradually because it could communicate to each other without infrastructure base stations. Due to limited power, routing path is broken easily, so how to design an effective power saving routing protocol is an important issue in wireless ad hoc networks. To solve this issue, we propose a new routing protocol called power saving routing protocol with power sieving (PSRPS) in this paper. The proposed protocol partitions the network area into several square grids by the location information such as global position system (GPS). Routing is performed in a grid-by-grid manner. One node is elected as the grid leader in its grid with power sieving mechanism without broadcasting election packets. Therefore, nodes could save more power for data transmission and the network lifetime could be prolonged. The simulation results demonstrate PSRPS could reduce power consumption from 10% to 18% compared with the traditional grid-based routing protocol.