Abstract: The valve is installed in the boiler superheater outlet and reheater inlet and outlet of the steam pipe, as a static water pressure test isolation device.During the operation of the boiler, various defects will occur due to the influence of various factors, among which cracks are the most dangerous defects, which are very likely to cause leakage or cracking, resulting in major safety accidents of the boiler. This article will analyze the causes of the cracks found in the valve blocking inspection, and propose some treatment methods.