The hydrothermal method to deposit lead zirconate titanate (PZT) thin film is a new method reported by Tsurumi et al. . in 1991. This method consists of two linked processes. We have found that the film deposited by the first process is not PZT but separated lead zirconate (PZ) and lead titanate (PT). In this paper, we report that a PZT thin film was successfully deposited by a single process. The chemical construction and composition of the film were analyzed. The Zr/(Zr+Ti) ratio of the PZT film was controlled by changing the ionic composition of the solution.