Abstract: The concrete performance in a low temperature is still a trouble spot. Freezer was used to cooling concrete blocks, and the blocks are the same strength grade. Then test the compression strength and tensile strength in the testing machine. This experiment studies the strength changes of concrete in a low temperature in detail. The test results prove that the compression strength and tensile strength of concrete are all increase with the decrease of temperature. But they are not in the same ratio. On this basis, and by compared with the data founded in the foreign literature, data fitting is used to get the function relationships between the strength and the temperature.