A deployment optimization algorithm using depth adjustable nodes in underwater acoustic networks is proposed to improve the effective coverage of the network and the monitoring quality of the target area. The nodes in the algorithm form the topology with the sink node as the root node through depth adjustment to achieve-full connectivity of the network. Node deployment is optimized by finding the optimal location of the node, with the connectivity between nodes remaining as a constraint. Simulation results show that the proposed algorithm achieves a significant improvement of effective coverage. When the number of nodes is 60 and the perceived radius is 0.8 km, the effective coverage is 11.87% higher than a voronoibased depth adjustment scheme or 12.59% depth adjustment selfdeployment of sensors for maximized coverage. At the same time, the network topology is more stable, and the performance is better in a dynamic underwater-acoustic network.