Abstract: Calcification is an important sign for diagnosing bone diseases.However，the calcifications located in bone region with high intensities have low contrast.An improved enhancement algorithm on calcification regions is presented.The proposed method designs a better desired histogram according to calcification intensity，then evolves the image using a Partial Differential Equation（PDE） according to its global information and local gradient information to get a resolution as the final enhanced calcification image.This algorithm is tested on the region of interesting of the digital bone CT image dataset which is collected from Women’s Hospital School of Medicine Zhejiang University，and good results are achieved.