The invention discloses a polarization SAR image segmentation method based on characteristic value measurement spectral clustering. The method mainly solves the problems that the number of parameters is large and adaptive adjustment is difficult to carry out in the existing polarization SAR image segmentation process. The method includes the steps of 1, carrying out eigenvalue decomposition on a polarization SAR image to form a feature sample set x, 2, solving corresponding mean values of three eigenvalues in an 8 neighborhood of each pixel to form a mean feature sample set, 3, respectively building a similarity matrix for the feature sample set x and the mean feature sample set utilizing mahalanobis distance so as to obtain a mixed similarity matrix w' according to the two similarity matrixes, 4, obtaining a clustering label C1 of the mixed similarity matrix w' through the spectral clustering algorithm, and 5, repeating the steps 3 and 4, integrating obtained class label sets by utilizing the MCLA so as to obtain a final segmentation result. The polarization SAR image segmentation method has the advantages of being high in adaptivity, low in complexity, detailed and accurate in segmentation result, and capable of being used for target detection and target recognition of the polarization SAR image.