In this paper, Particle Swarm Optimization (PSO) is introduced into Optical Wireless Sensor Networks. We consider the impact of node location on energy consumption when communicating over the network. The algorithm use PSO to optimize the position of nodes with the lowest energy consumption. The proposed method converges faster. By optimizing the positioning of node, energy consumption of the node is effectively reduced and the overall performance of the network is improved. An energy-saving optical wireless sensor network is obtained.