The issue of deployment strartegy of sensor nodes to extend the lifetime of multi-hop wireless sensor network is addressed. Based on load-balancing concept, an algorithm is proposed to deploy homogeneous sensor nodes in a wireless sensor network with a given number of sensor nodes which are continuously monitoring an area of interest. The densities of sensor nodes are determined by solving an optmization problem which maximizes the coverage percentage under the constaints that the traffic loads among sensor nodes af different distances are equal. Simulations are performed by using the proposed algorithm accompanied with energy-efficient clustering and gradient-based routing algorithms. The simulation results indicate thut, for a given number of battery-powered sensor nodes, the network with sensors deployed in the proposed distribution can sustain for extended lifetime and break down more gracefully than that for 2-D Poisson distribution whilemaintaining satisfactory coverage.