The present disclosure provides a photosensitive assembly and formation method thereof, a lens module, and an electronic device. The method for forming the photosensitive assembly includes providing a transparent cover plate; providing a photosensitive chip, including a photosensitive region and a peripheral region surrounding the photosensitive region; bonding the transparent cover plate to the photosensitive chip through a bonding layer, the bonding layer located in the peripheral region of the photosensitive chip, and the transparent cover plate, the bonding layer, and the photosensitive chip enclosing a cavity that accommodates the photosensitive region; and forming a sealing layer to at least cover the sidewall of the bonding layer and the sidewall of the transparent cover plate. According to the present disclosure, a sealing layer is formed on the sidewall of the bonding layer and the sidewall of the transparent cover plate to increase the effect for sealing the cavity. In a subsequent packaging process, the sealing layer may prevent liquid, e.g. water, from entering the cavity, thereby improving the waterproof ability of the photosensitive assembly, and thus improving the reliability of the lens module.