The heat treatment technology of P92 steel is studied by comparison of the tension properties, observation of the metallurgical structures and the fracture topographies analysis. It is shown that the ultimate tensile strength decreases and the ductility increases with the tempering temperature increasing in the range of 200℃~700℃, and the change reverses when the tempering temperature is in the range of 700℃~900℃. The optimal tempering temperature for P92 steel is 700℃ in consideration of the static toughness when it is tempered below A_C1.