The stability of feature vectors based on SVD decomposition is very low for the variation of target′s size and orientation. On this problem mentioned above, a new target feature extracting method is presented. It is a matrix describing method based on scale transformation. These matrixes of all same kind of target samples getting through transformation mentioned above have the similar energy. The matrix method proposed extracting target′s features from SVD feature values can overcome shortcomings of extracting SVD feature directly from matrix of the images. The experimental result shows this method has favorable stability to target matrix′s SVD feature vectors, and high invariant property to displacement, rotation and scale. It is a practical feature extracting method.