The creep experiments are performed under the various stresses at 595°C, 610°C, 640°C and 670°C for P92 steel which broadly used in USC plant pipeline. The specimens are taken from the extrados part of a new manufactured main steam elbow. A series of integrated creep curves are obtained, and the maximal test time last over 13000h. The relationship between the minimum creep rate and stress at different temperatures is explained by Norton formula. Both the 105 h creep rupture strength and stress of 1% creep strain in 105h of P92 steel at the four above temperatures are extrapolated with a list by using the Monkman-Grant formula, which are consistent with the reference experiment data at 600°C and 650°C. Meanwhile, damage during the creep process is discussed applying Norton creep damage formula and θ function method.