A computer-implemented video analyzing method includes dividing a video into a plurality of sections. The similarity value of the first frame and the last frame of each section is greater than zero. A representative frame is selected from each section, and the similarity value of each two representative frames is computed. Two sections the similarity of whose representative frames is the greatest are combined into one section. The recording time of the first frame and the recording time of the last frame of each section is determined if the similarity value of representative frames of each two adjacent sections is zero.