This paper proposes a two-dimensional constrained adjustment method with fused depth difference and a three-dimensional constraint adjustment method with additional depth by using the depth information from pressure transducer,in order to solve the problem of unstable vertical solutions in traditional underwater control network solutions. The considered problem exists in a control point coordinate that is determined based on a three-dimensional space distance intersection. Applying the former method with a given depth difference,the underwater control point coordinate can be determined by transforming the three-dimensional space intersection problem into a two-dimensional plane intersection problem and then constructing an adjustment model in the two-dimensional plane. Applying the latter method,the underwater control point coordinate is determined by solving the space distance equation combined with high precision observations and constrained conditions of the depth. We carried out experiments in Songhua Lake,and the experiment results show that the calculation precision of underwater control point coordinates is improved 2~5 times by applying both two methods. It implies that introducing the depth information into the calculation process of underwater control network and then constructing adjustment model can be helpful to improve the stability and precision of the three-dimensional solutions of the control network coordinates.