The present invention relates to a method of providing a routing protocol in a sensor network. The routing protocol is a new model which is made considering a battery efficiency so that an AODV protocol, which is widely used because of its simplified and reliable algorithm, can be matched to a sensor condition. An energy information of a node is contained in the RREQ message of the AODV, thereby allowing the neighboring nodes and the nodes on the path to know their energy states. The method of providing a routing protocol in a sensor network includes the steps of: initializing a routing table and searching a network device of a node to initialize a host; opening a socket when there is a request for forwarding of an IP (Internet Protocol) packet from an upper layer or when there is a request through the network device; determining whether there is the IP packet forwarding request of the upper layer node or whether the packet is received from the network device; if there is the IP packet forwarding request of the upper layer, searching the routing table, and determining whether or not there is a destination node which intends to transmit the packet, and returning to a main loop if there is the destination node; and if the packet is received through the network device, determining types of the received packets and performing RREQ process, IDLE process, RREP process, RERR process, and RREP_ACK process.