Abstract: Fatigue property of RPV steel is one of the most key parameters in the RPV design life evaluation. The fatigue tests of domestic A5083 steel under the simulated AP1000 primary coolant environment were carried out, the fatigue data of 0.04%/s strain rate, 321 ℃, 15.5 MPa and 0.1 ppm dissolved oxygen were obtained. The results show that the peak stress increases as the strain amplitude. During the fatigue test, the specimens show three stages: Cyclic hardening, cyclic softening and saturation. Fatigue life decreases from 105 to 102, as the strain amplitude increases from 0.2% to 0.6%. The fatigue fracture surface morphology has the characteristics of fatigue and corrosion, which indicates the typical corrosion fatigue fracture.