Abstract: Sensing range is the maximum range within which a sensor node can detect a target. This paper proposes an energy-efficient scheme for area coverage in wireless sensor networks with adjustable sensing ranges. The scheme assigns reasonable sensing ranges to the network of nodes to minimize the energy consumption and meanwhile meet the coverage requirement. Firstly, the coverage capability and energy consumption are formulated as functions of node sensing ranges; Then, the area coverage issue is formulated as a constrained optimal model; Finally, a area-divided-based method is developed to solve the problem. Simulated results show that, compared with traditional method, the proposed scheme can efficiently save energy with satisfactory area coverage.