Abstract: This paper gives an auto-restorable fragile watermarking algorithm for image content authentication, which can not only detect the location of any changes in images but also restore the altered image content. Firstly, the low frequents sector picked up by discrete wavelet transform(DWT) as watermarking. Then the RS correct-encode technology is used to encode the watermarking. Finally, the watermarking data are embed into the lowest bits of the image data after being changed with arnold shuffling techniques and chaotic encrypt tentechniques. Experimental results demonstrate that the watermarking algorithm is a valid fragile digital image watermarking algorithm.