Abstract: In order to solve the problem of trend surface conformation,a new method of constructing trend surface by LS-SVM is presented,and then outliers of Multi-beam data could be eliminated by the trend surface.In order to illuminate the correctness and rationality so a contrast between this method and the approach of trend surface filter.The theorem proves that the trend surface filter is the especial result of LS-SVM.The example shows that in the process of constructing trend surface by LS-SVM,the weight parameters could be adjusted,so the trend surface have the property of popular and steady,the outliers of Multi-beam data could be eliminated effectively.