The mechanical properties of concrete under low temperature subjected to subzero temperature curing or varied curing conditions were investigated. The development rule of compressive strength and dynamic elastic modulus were obtained. Hydration process and morphology of hydration products were analyzed by microscopic observation. The results show that concrete without anti freezing agents showed rather low strength at -10℃, anti freezing agents could effectively reduce micro cracks of concrete induced by subzero temperature curing at early hydration stage.