Abstract: The existing algorithm of ship propeller blade-number recognition is based on mathematical model or expert system.The result of blade-number recognition is usually instable and inaccurate, in the case of DEMON line spectrum of ship radiated noise at low signal-to-noise ratio(SNR).This paper proposed a method for ship propeller blade-number recognition based on template matching.This method establishes a template library, which is independent of samples.Template Matching algorithm and confidence factor algorithm are designed.This method can resolve the problem of inaccurate mathematical model, incomplete rules and samples in existing algorithm.Practical experiments prove that the error rate of propeller blade-number recognition is reduced distinctly, and the result of target classification goes toward stability.