At present, the more common materials of exterior insulation in our country are the external heat-insulation wall of polystyrene panel, aerated concrete blocks and thermal insulation coating. Paper analyzes the advantages and disadvantages of these three technologies. The results show that with the same thermal insulation property, the cost of thermal insulation coating is obviously lower than the other two. Meanwhile, the thermal insulation coating has a significant improvement on the anti-fire properties, which can eliminate the potential fire risk which may be caused by the external wall of polystyrene panels. In addition, the thermal insulation coating is more simple to construction. Finally, this paper introduces the development prospects of thermal insulation coating.