To study the mechanical properties of Q235 steel frame girder in different corrosion degrees, low frequency cyclic loading test on steel frame girders of six trusses in different corrosion degrees was carried out on the basis of seismic performance test of steel frame girders. The hysteresis curve, skeleton curve and rigidity degeneration rule were obtained based on the text results. The effect of different corrosion degrees on seismic performance of steel frame beams was acquired by analyzing text data. The cyclic degradation index was introduced, and the characteristic point (yield point, limit point and breaking-down point) formula with cumulative damage effect was fitted. The hysteretic rule applied to rusted steel frame girders was put forward，and then the restoring force model of steel frame with the consideration of corrosive action was established. The comparison between the simulation curve and text curve for the samples of three trusses was performed, and the comparison between the simulation curve and finite element analysis for other samples of three trusses was implemented. The comparison results show that the restoring force model has high precision and better tally, the established restoring force model can provide theoretical basis for the analysis on steel frame girders in different degree of corrosion and lay a foundation for elastic-plastic analysis steel frame girder in different degree of corrosion