In this paper, the chaotic time series RBF neural network model was designed. A prediction method for underwater acoustic chaotic signal based on RBF neural network is proposed in this paper according to the characteristics of chaotic signal with the short-term prediction. Typical Henon chaotic signal and the actual underwater acoustic chaotic signal are respectively predicted by the RBF neural network. Then the prediction results are analyzed. The results show that the proposed prediction method increases at least two orders of magnitude in the mean square error terms compared with existing prediction method, and that the RBF neural network can be used to predict the chaotic signal effectively.