In order to predict the health of civil aircraft hydraulic system, based on the LS-SVM regression under Bayesian evidence framework model, the Radial Basis Function (RBF) kernel is used. The LS-SVM regression parameters are selected and tuned, the model algorithm and interval prediction formula are selected, and then the prediction model of hydraulic system is built by the train sample, the validation of formula is verified by the test sample. The parameters of hydraulic system are predicted, and then the predicted values are put into the health assessment model. The results show that the LS-SVM regression under Bayesian evidence framework model is able to be well applied to the health prediction of civil aircraft hydraulic system.