Abstract: In the past years, the low- and high-cycle combined fatigue （L-HCCF） testing has been studied by many investigators. However, the L-HCCF crack propagation behavior at elevated temperature has scarcely been reported. In this paper, the L-HCCF crack propagation behavior described by stress intensity factor at 600癈 for a superalloy GH36 is presented. It was found that the rate of L-HCCF crack propagation per block, da/dN, appeared a f-shaped curve, may be divided into two regions:1) the slow propagation region, where the crack propagation is dependent primarily on the damage induced by the low cycle fatigue load; 2 ) the fast propagation region, in which the vibration loading becomes a dominant factor. A transition point between two regions, Kminor=3.5-5MPa m, can be explained with fatigue threshold value Kth（R）. The vibration loading appeared to restrain the creep damage at elevated temperature and an interaction among LCF, creep and HCF in the course of the L^HCCF crack propagation was noted, where the linear cumulative damage law was inapplicable.