An optical analysis method is provided for judging whether a lens and a sensing element of an image pickup device are parallel with each other. The method utilizes a tested image pickup device and a standard image pickup device to shoot an object at the same fixed shooting position to acquire a standard image frame and a tested image frame. According to the difference between the position coordinate value or the area of at least one mark of the standard image frame and the tested image frame, the method can judge whether the tested lens and the tested sensing element of the tested image pickup device are parallel with each other.