Abstract: Low cycle fatigue characteristics of 10CrNiMo high-strength steel were investigated with smooth rotundity-section specimens through low cycle fatigue testing under axial loading controlled by different strain amplitudes, including cyclic stress-strain behavior, strain-life feature, cyclic stress response and mechanical hysteresis. The relevant fatigue parameters, cyclic softening/hardening property and strain hysteretic rule were given on the basis of experimental data. Observations of crack propagation orientation and frac-ture surfaces show that fatigue cracks initiate with multi-initiation sites from the specimen surface, distribute along the fracture border, and propagate along planes with different angles to axial force. Fatigue crack propagation is mainly in the blunting-resharpening mechanism.