Abstract： Fatigue crack growth rate (FCGR) data of three kinds of alloy 690 by different manufacturing process were generated in air at room temperature and 325 ℃ using the pin-loading tension (PLT) specimen and direct current potential drop (DCPD) method. The testing data were modeled with the Paris-Erdogan equation, and a linear relation between log(da/dt) and log(ΔK) was observed, which indicated good veracity and reliability of results. The threshold stress intensity factor amplitude ΔKth of the three alloys was predicted from the fatigue crack growth curve at 325 ℃, and material B has the highest ΔKth, showing best fatigue resistance performance. Scanning electron microscopy (SEM) examination of the fatigue fracture surfaces revealed transgranular attack, and the transgranular regions of the fatigue fracture surface were covered with striationlike features, indicative of micro-plastic deformantion.