An image authentication algorithm based on feature of image and hyperchaotic iteration is proposed. The stable feature value is attained by extracting the edge of low-frequency components from wavelet transform of the original image. In order to get the indices set, hyperchaotic iteration is executed by combining the value with the information of watermarking. So the indices set is signed and timestamped by the owner and the trusted third party's private keys. By using the public keys, the image of watermark can be authenticated without the original image. The experimental results show the algorithm is robust to noise adding, filtering, compression, rotation.