Wireless Sensor Networks (WSN) are an emerging and very interesting technology applied to different applications. They are formed by small, self organized devices that cooperate to form a large scale network with thousands of nodes covering a large area. The independent operation of the devices and the self-organization feature of the network present some challenges related to security, particularly regarding the security of the processed and routed data over the network. WSN are generally used to monitor activities and report events, such as fire,overheating etc. in a specific area or environment. It routs data back to the Base Station (BS). Data transmission is usually a multi-hop from node to node towards the BS. Sensor nodes are limited in power, computational and communication bandwidth.Primary goal of researchers is to find the energy efficient routing protocol.This study highlights the different routing protocol with advantages and limitations.