The main reason of the quality accident of Polyurea spraying project is the fact that the proportion of the project with some domestic raw materials is high. In recent years, commissioned by the owners, our company has been the construction of a number of short-term use only to complete the removal of similar works. The main problems of some domestic materials are unstable quality, low film-forming strength, poor adaptability to construction environment (for example, low temperature, relative humidity), easy to produce bubbles, and high odor when spraying. Although spraying Polyurea technology is a special new process, it still needs to be based on reliable coating technology. Some engineering accidents are entirely due to the lack of basic coating technology. For example, one of the Polyurea projects that we have been entrusted to do thoroughly originally asked to spray 1.5mm, but after stripping found the thin in 0. Below 5mm, the thickness of up to 4mm above, or even the bottom of the local coating by viscous and brittle, such as a variety of materials stacked adhesion, the total thickness of 6mm, thickness difference up to 10 times times, construction technology quality is obvious. But spraying Polyurea has its very special technical requirements, the influence of air temperature on material balance, the special requirements of basic level, the identification of raw material quality, the accurate control of some process parameters, and so on, only the traditional coating technology is far from enough, this is some professional waterproof units also do not spray Polyurea project important reasons.