One of the important inelastic characteristics of reinforced concrete columns during the strain-softening stage is the buckling and the fracture of longitudinal reinforcement after tension-compression cyclic loading. However, there are few low cycle fatigue damage models considering the influence of buckling, and a few fatigue damage models considering buckling cannot be directly used for fatigue damage calculation and fracture analysis of steel bar with different strength. In this paper, the specimens of HRB400 reinforcement and HRB500 reinforcement with slenderness ratios of 6.25, 9.375, 12.0 and 15.0 were subjected to tension compression equal cyclic loading and tension compression unequal cyclic loading considering buckling respectively. The average stress-strain (σˉs-εˉs) curves and mid-span transverse displacements of buckled specimens were measured. Combined with the corresponding test results of HRB600 reinforcement completed by the author, a systematic test data was constituted. Based on the test results, the effects of yield strength and slenderness ratio on the ultimate deformation capacity of buckled reinforcement were analyzed, the applicability of the traditional low cycle fatigue damage model (C-M model) and the modified C-M model based on the total average strain amplitude εˉsa to the buckled reinforcement was investigated, and the errors were analyzed. A modified C-M fatigue damage model based on cyclic total average strain amplitude εˉ_sa-cyc with good applicability was proposed. The results show that specimens with different strength have different low cycle fatigue performance due to the different mechanical properties of steel bar, such as εsu，εsult and fu etc. The ultimate deformation capacity of buckled steel bar under cyclic loading is related to low cycle fatigue damage, the fracture of steel bars cannot be correctly determined by the ultimate tensile strain εsu under monotonic tension. The modified C-M model based on the total average strain amplitude εˉsa cannot reasonably consider the influence of different loading methods on the low cycle fatigue life of buckled reinforcement, and there are systematic errors. The modified C-M model based on εˉ_sa-cyc can reasonably consider the influence of different loading methods, and can be directly used for reinforcement of different strength and slenderness ratio with small error.