The invention relates to the technical field of digital content safety protection, in particular to a quickly generating method of a user copy based on a video GOP (Group of Picture), which is based on a cascade fingerprint code technology. The user-copy generating process comprises the following steps of: generating female copy video source files according to an internal code sequence of a fingerprint code; according to an external code of a user, sequentially extracting corresponding image block groups from the corresponding female copy video source files; and generating an only user copy by combining and splitting the GOP image block groups. The invention reduces time for generating a user video copy to time for copying a video resource from time for coding a video resource, can quickly generate large numbers of video copies in short time and is suitable for a real-time on-line publication system of audio-video works which face to large-scale users. The provided algorithm of the invention has good universality and good practicability and can be suitable for common video coding standards, such as H.264, MPEG(Motion Picture Experts Group)-2, MPEG-4, AVS (Advanced Visual System), and the like.