Abstract: Through analyzing the principle of predictive coding,a steganalysis method based on predictive coding is proposed.The predictive coding is based on the relativity between the neighboring pixels.On the coutrary,steganograph will destroy the relativity between the neighboring pixels.Through computing and analysing the predictive error of cover image and steg image,it is obtained that steganograph will(increase) the predictive error.So the predictive error can be used to detect steganograph.The experiment shows that this method has a better ability of steganalysis.