A waterproof light head structure includes a main bracket, a front cover and a rear cover respectively arranged on the front side and the rear side of the main bracket, an upper plate arranged above the main bracket, a bottom plate arranged below the main bracket, a lens assembly arranged on the main bracket via the upper plate, and a light source arranged in the main bracket. The main bracket is arranged in a cavity formed by joining the front cover and the rear cover. The front cover and the rear cover are respectively in sealed connection with the upper plate and the bottom plate, and the side edges where the front cover and the rear cover are joined are in sealed connection to form an all-around waterproof structure. The waterproof light head according to the present invention is simple in structure, while the waterproof performance is guaranteed.