Abstract: Monotonic tensile tests and cyclic loading tests with constant strain amplitude are implemented on HRB400 steel, and the basic mechanical performance parameters, strain amplitude-fatigue cycle expression, strain amplitude-strength degradation coefficient expression, and fatigue parameters of the steel are defined. Based on the material performance parameters, a test simulation using the Reinforcing Steel model in OpenSees verified the accuracy and practicability of the test results. In the end the low cycle fatigue properties of HRB400 steel are evaluated and an experimental basis for precise nonlinear numerical modeling for RC structures is developed based on a material fiber model.