A light source module comprises a light source, a distance sensor and a processor. The light source is adapted to provid a light to an irradiated area. The distance sensor and the light source located in the same plane. The distance sensor is adapted to sensing a distance from the distance sensor to the irradiated area. The processor is electrically connected to the light source and the distance sensor. The processor adjusts the luminous intensity of the light source according to the distance sensed by the distance sensor. In addition, a phototherapy apparatus and method of use thereof are also provided.一種光源模組,其包括光源、距離感測器以及處理器。光源適於提供一光線至待照射區域。距離感測器與光源位於同一平面,距離感測器適於感測出光源至待照射區域的一距離。處理器電性連接於光源與距離感測器,處理器依據距離感測器所感測出的距離調整光源的發光強度。另外,一種光療裝置及其使用方法亦被提出。10‧‧‧待照射區域30‧‧‧使用者50‧‧‧光療裝置100‧‧‧光源模組110‧‧‧光源112‧‧‧線路基板114‧‧‧發光元件120‧‧‧距離感測器130‧‧‧處理器140‧‧‧主體142‧‧‧容納空間144‧‧‧內壁150‧‧‧透光板160‧‧‧光源感測器170‧‧‧標記光源180‧‧‧影像擷取裝置D‧‧‧距離LH‧‧‧治療光線LM‧‧‧標記光線LS‧‧‧感測光線LS’‧‧‧反射光線