Abstract: Entropy based thresholding is an important method of image segmentation and is used in the image processing for many applications.This paper considers that the method of thresholding based on maximal entropy，which requests system interior satisfying uniformity hypothesis of image gray level distribution，is not suitable to segment some images.New method of thresholding based on weighting information entropy is proposed in this paper，and then discuss how to choose weighting factor of weighting information entropy for image segmentation.In the end，the new evaluating method based on intra-class and inter-class entropy is put forward.The experimental results show that the method of this paper is feasible.