The high pressure boiler is made by thick-wall seamless steel tube. It applies to steam conduit and water supply conduit used for the supercritical boiler and the ultra supercritical boiler. Its specifications are as follows: the outside diameter is Φ300 ~ Φ1200, and the length is 4 m to 12 m. The materials used is 12Cr1MoVG, 12Cr2MoG, SA_106C, P12, P22, and P91. In addition, it has the features of good compactness, high cleanliness, high-temperature mechanical property and high creep rupture strength. Moreover, NHIG has the production capacity of producing 10,000 tons of thick-wall seamless steel tube used on high pressure boilers with various specifications.