Abstract: A fast iterative method of mode decomposition for a short vertical array has been presented in 6. The key advantage and practical application is to reduce the length of the vertical array. In this paper, a weighting method of MMP with the iterated mode amplitude vector, by using some linescomponent spectrum of radiated noise of a small speedboat, is proposed. The numerical simulated results of the multi-line spectrum weighting method show that the accuracy of source range and depth estimators are raised, and the sidelobes are effectively suppressed. It is excellent to one-line spectrum localization with the highest level of 100Hi of this speedboat.