Described is an intelligent fast-forward video system that automatically controls a relative play speed of the video based on a complexity of the content reflecting the real story of a video, thereby enabling to carry out a fast-forward viewing for summarizing an entire story of a digital video or moving fast to a major concerning part. The present invention obtains the complexity of the content using information of motion vector, shot, face, text, and audio for an entire video and adaptively controls the play speed for each of the intervals on a fast-forward viewing of the corresponding video on the basis of the obtained complexity of the content. And, in more detail, the present invention plays a complicated story interval relatively slow and a simple and tedious part relatively fast, thereby enabling to provide a user with a summarized story of the corresponding video without viewing the entire video as well as a fast search for a part wanted by the user.