To understand concrete mechanic properties under various pH values of water surroundings and freeze-thaw cycles，accelerated corrosion test, uniaxial compression test and three-point bending test with initial crack were conducted to examine macroscopic mechanical properties and fracture strength of concrete after its dipping in solutions with diffrent pH values and then undergoing freeze-thaw cycles. In addition, the scanning electron microscope (SEM) images of concrete obtained were analyzed by image-pro plus (IPP) software to reveal the deterioration of concrete experiencing corrosion of surroundings and freeze-thaw cycles together. Results show that although the pH values have different relations with separate mechanical properties, damages towards mechanical properties from freeze-thaw cycles go up with the decrease of pH values. The internal microscopic deteriorations of concrete specimens after dipping in solutions with different pH values are similar. There is a quadratic function relationship between the loss variable and the number of freeze-thaw cycle. The damage variable formulas applicable to situations with various pH values of solutions and different freeze-thaw cycles are finally derived.