A method for analyzing a number of people includes an image shooting step and a front-end analyzing step. In the image shooting step, a first image and a second image are obtained. In the front-end analyzing step, a foreground object analysis is operated, and a plurality of foreground objects located at a region of interest in the first image are obtained. A human body detection is operated, and at least one human body and a location thereof of the second image are obtained. An intersection analysis is operated, and the location of the human body is matched to the first image. A number of people estimation is operated to estimate the number of the people according to the first covering ratio, a number of the human body, and a second covering ratio of all the foreground objects to the region of interest.