Digital image scrambling degree is one of the most important aspects of evaluating digital image scrambling algorithm，it has significant effects on the research of digital watermark algorithm. It can describe the best effects of digital image scrambling by taking the frequency of gray levels. Using the best effects of digital image scrambling as parameters

this paper has presented a new method of measuring digital image scrambling degree based on the frequency of gray levels. Emulational experiments have been carried out in MATLAB. The results of the experiment have suggested that the digital image scrambling degree evaluation method is the same as all sorts of image encrypting. The resulting digital image scrambling degree is accordant with visual subjective evaluation

it would not differ a lot for the sake of the changing of its former image as well.