Abstract: In order to investigate and analyze the fatigue life of the low alloy steel of domestic reactor pressure vessel in pressurized water reactor coolant environment, experimental material was cut down from actual reactor pressure vessel product forgings are sampled and processed into test specimens. Low cycle fatigue tests have been performed using the high temperature and high pressure water fatigue testing system, the fatigue data and the effects of the strain rate on the fatigue life were acquired, and the relationship between testing data and ASME code design/mean fatigue curve was analyzed. The suitability of ASME code design fatigue curve and fatigue life environmental correction factor was evaluated.