The invention relates to a steel-plastic composite pipe spraying device, which comprises an electrostatic spraying system for spraying the outer surface of a steel-plastic composite pipe, an inner powder spraying system for spraying the inner wall of the steel-plastic composite pipe, a pre-heating system, a solidifying system, a transportation system and an electric control system for controlling the entire device, wherein the pre-heating system consists of a pre-heating furnace, a pre-heating system fan and a pre-heating system heater, which are connected with the pre-heating furnace; the solidifying system consists of a solidifying furnace, and a solidifying system fan and a solidifying system heater, which are connected with the solidifying furnace; the transportation system consists of a feeding bracket, a discharging bracket, and a pre-heating system transportation track and a solidifying system transportation track, which hare driven by a motor, and a translation bracket for controlling the steel pipe to move among the pre-heating system, the solidifying system, the electrostatic spraying system and the inner powder spraying system, the pre-heating system is arranged behind the feeding bracket, the electrostatic spraying system and the inner powder spraying system are arranged between the pre-heating system and the solidifying system, and the discharging bracket is arranged behind the solidifying system. The steel-plastic composite pipe spraying device has the advantages of reasonable structure, high automation and high efficiency, has good powder spraying effect, can realize the automatic, continuous and stable production, and has good energy conservation and environmental protection as well as good economic benefit.