Abstract: Corrosion fatigue behavior of SS316LN was investigated in high temperature water environment, under strain controlled loading. During the loading process, the phenomenon of first hardening and then softening occurred, and the peak stress has a drop after a rapid ascent with the rising of cycles. The fatigue life of 316LN decreases at high temperature in pure water and water with H3BO3 and LiOH, because high temperature and corrosive environment accelerated the corrosion fatigue failure of the 316LN. Under the condition of high strain amplitude, high temperature plays a major role in corrosion fatigue failure, while corrosion plays a major role in the condition of low strain amplitude. Fatigue striation, slip deformation zone and secondary crack can be observed on the cross section of the sample after the test. High temperature water corrosion environment will accelerate the crack growth and the fatigue failure of 316LN.