The invention provides a sensitive bulb. The sensitive bulb comprises a shell structure, an optical cover, a transparent cover, a first carrier, an event sensing circuit and a brightness sensing circuit, wherein the first carrier, the event sensing circuit and the brightness sensing circuit are arranged in the shell structure; the event sensing circuit is used for detecting whether a triggering event occurs in a sensing range or not; the brightness sensing circuit is used for detecting the brightness of the sensing range; the optical cover is arranged at a first opening end for exiting of light of the shell structure; a first side surface of the first carrier faces the first opening end; the transparent cover covers the first side surface of the first carrier so as to form a cavity between the transparent cover and the first carrier; and the event sensing circuit and the brightness sensing circuit are arranged on the first side surface of the first carrier and are positioned in the cavity.