Abstract: From the entire process of deteriorated performance of bending fatigue damage,combined with residual strain and accumulated energy release,the second linear and steadily developing phase was described,which almost occupies 80% of the whole fatigue life.Aimed at the second phase of fatigue damage,the durability of structural concrete under the effect of multi-factors of fatigue loading and environmental factors was investigated mainly in the paper.As the residual strain exceeds 60 10-6,both the diffusion coefficient of chloride ion and the air permeability coefficient increased with the increment of residual strain.Especially,when the residual strain is 120 10-6,the corresponding coefficient raised 10 times.In the case of freeze-thaw cycles,there is also the same tendency.Therefore,the values of residual strain from 30 10-6-60 10-6 and its 120 10-6 are considered as the starting range and the accelerating point of affecting the durability of structural concrete,respectively.