Abstract: The chromium element was introduced by adding 430L stainless steel powder to base powder. Fe-1.65Ni-1.4Cu-1Cr-0.5Mo-0.6C iron-based alloy was prepared by powder metallurgy, and then was treated by hardening and tempering heat treatment. The bending fatigue behaviors of the alloy under 10⁵-10⁸ cycles were studied. The results show that the high and ultra-high cycle bending fatigue curve of the tested alloy exhibited a continually falling trend, and there was no fatigue platform. The cracks on fatigue fracture initiated from multiple sources. The cracks initiated at the defects in surface and sub-surface of the tested alloy under high stress amplitude, and initiated at inner faults of the tested steel under low stress amplitude. Crack propagation region had an obvious fatigue striation feature. Under high stress amplitude, the striation space in crack propagation region was relatively big, indicating that the crack growth rate was high, compared with that under low stress amplitude. The rapid fracture region was composed of cleavage planes and small dimples. There were more cleavage planes and fewer dimples in rapid fracture region under low stress amplitude than those under high stress amplitude, indicating that the brittle fracture was more obvious.