1. A photo composition method, adapted to an image capturing apparatus having a first lens and a depth sensor, wherein the method comprises the following steps: obtaining a preview frame of a scene by using the first lens; obtaining depth information of the scene by using the depth sensor; performing scene analysis on the preview frame according to an area of a region within a specific depth interval in the preview frame based on the depth information so as to generate a scene analysis result, wherein the scene analysis result comprises an outdoor scene, a close-up scene, and an indoor scene; determining whether the preview frame satisfies a photo composition requirement according to the scene analysis result and a corresponding photo composition rule; if yes, controlling the first lens to capture the preview frame; and if no, providing a photo composition suggestion corresponding to the scene according to the photo composition rule corresponding to the scene analysis result.