The thesis expounds the basic principle and method of data mining and phase - space reconstruction theory, and discusses its application in the prediction of dam crack. The combined method of chaos reconstruction and data mining model is very effective for discovering the complex nonlinear structure of dam crack. It is proved that the application of the model above is practicable and reasonable on the basis of practical examples researching and in comparison with the predicted results obtained by unitary chaos reconstruction theory. And it has high predicting accuracy and much applicable significance.