The relationship between the laser power output and its effect on Raman spectrum is investigated for a laser cleaning application of marine metal corrosion processing. First, an image feature based on a corrosion degree evaluation is implemented before cleaning. The image features include texture coarseness, texture entropy, texture intensity, texture contrast, the texture’s cluster degree, and texture homogeneity. To decrease the image feature dimension for a convenient application, the Analytic Hierarchy Process (AHP) method is used to estimate the weight of each feature. Then the linear weighted sum of image features can be computed to get only one evaluation result. Second, a series of laser power outputs are implemented for the cleaning application under a typical corrosion degree. Then the analysis results of Raman spectrum can be obtained. The analyzed spectrum results include the corrosion components and their contents. Lastly, the relationship between laser power output and Raman spectrum under a typical initial corrosion degree can be constructed. This research study can build the prediction result of the cleaning effect map for the workpiece and guide the secondary processing of metal surface cleaning.