Zero watermark is a new research direction of the digital watermark technique. It availably solves the antinomy between robustness and imperceptibility, and protects the copyright of image better. On the basis of the attacks the application of digital watermark is facing and the existence of security risks of DHWM Protocol, in this paper we put forward a new safe zero watermark Protocol based on time-stamp and digital signature. The protocol introduces digital certificate, through the extraction of important information in images to generate zero watermark with digital signature and time-stamp as specific information. The Protocol can resist intermediary attacks and explain attacks through security analysis and performance analysis, with no real sense of visibility and high security it can be applied to the actual copyright protection of digital image.