A 3D node deployment algorithm is proposed based on Improved Particle Swarm Optimization (PSO) algorithm for underwater sensor networks.By adjusting the weighting factor of the PSO algorithm linearly, the comprehensive deployment of the current deployment area can be realized while avoiding local optimization of the nodes.The oscillations near the optimal deployment position can be eliminated too.Compared with the virtual force algorithm, the proposed algorithm can achieve the optimal deployment effect with a shorter time, and effectively ensure the connectivity between the network nodes while obtaining a high 3Dcoverage rate.