Low cyclic fatigue (LCF) properties of three kinds of high temperature alloys (Inconel-718, Incoloy-825 and Incoloy-800H) as candidate materials for supercritical water cooled reactor (SCWR) were investigated at 650 oC and room temperature (RT) under a strain amplitude of ±0.5%, and fracture morphology of all the samples was observed by scanning electron microscope (SEM). The results show that the fatigue property of 718 is the best at both temperatures. The temperature has few effects on the area of hysteresis and elastic deformation for each alloy. The area of hysteresis for 718 is much lower than that of 825 and 800H, while the elastic deformation of 718 is as twice as that of other alloys, which is beneficial for improving the fatigue life. The 718 alloy shows a cyclic softening behavior in the testing; however, 825 and 800H coincide with the hardening-saturation mode; in addition, their cyclic hardening behavior is more obvious at 650 oC. SEM observation finds that the fatigue striation width after LCF testing at 650 oC is no more than 1 μm for 718, but up to 2.28 μm and 2~20 μm for 825 and 800H, respectively, which further demonstrates that 718 has the best fatigue property at 650 oC.