Abstract: Described here in the essay are the manufacturing process and the product performance of the large-sized P92 seamless steel pipe as used for the ultra-supercritical thermal power unit.The said P92 pipe is developed and produced owing to taking such process-controlling measures as optimizing the chemical composition,controlling the rolling temperature,and properly determining the heat treatment scheme,etc.The P92 pipe possesses advantages such as homogenous microstructure,consistent mechanical properties and excellent hi-temperature creep rupture property.The newly-developed P92 pipe has been used for the four major pipelines and other critical components of the ultra-supercritical thermal power unit.