The influence and damage mechanism of frozen up time on the damage mode, compressive strength, splitting tensile strength, relative dynamic elastic modulus, permeability and pore structure of early frozen concrete were studied by the service performance test for the early frozen concrete with different frozen up times. The results show that the influence is the most significant for the concrete with frozen up time of 2.0hours, and the influence is next to that for the concrete with frozen up time of 05 and 8.0hours. Moreover, the damage degree of frozen concrete after final set（1,3d） is the slightest and reduces gradually with the increasing frozen up time. In addition, the degradation of splitting tensile strength is the greatest, the reduction of dynamic elastic modulus takes the second place and the degradation of compressive strength is slightest. Furthermore, the anti permeability of concrete with frozen up time of 3days is slightly worse than that of non freezing concrete, and the anti permeability of concrete with frozen up time of 1day is worse than that of 3days, the anti permeability of concrete frozen at 05, 2.0 and 8.0hours are the worst and even beyond the test range of AutoClam equipment. The pore structure of concrete frozen after final set is close to that of non freezing concrete with increasing frozen up time. With regard to the concrete frozen before initial setting time, the frost damage can be partially repaired, some visible cracks appear in the paste or paste aggregate interface, the chord length frequency of 0006mm reduces significantly and the air contents(by mass) under different chord lengths increase in varying degrees. For the concrete frozen between initial set and final set, notable cracks at the paste or paste aggregate interface and fine aggregate particles are observed, moreover, the chord length frequency of 170400mm and the air content of 200400mm increases significantly.