The invention relates to a method for establishing a mathematical model of damage rate evolution of recycled concrete under freeze-thaw, Because of the application of damage mechanics, The freeze-thawdamage degree of recycled concrete is defined by dynamic elastic modulus, and the freeze-thaw damage experiment of recycled concrete is designed. Then the relationship model between freeze-thaw damage degree of recycled concrete and different freeze-thaw cycles is established by quick freezing method, and the damage rate evolution mathematical model of recycled concrete under freeze-thaw is obtained. Therefore, the method for establishing a mathematical model of damage rate evolution of recycled concrete under freezing and thawing is based on macroscopic damage mechanics theory, and has a solid mechanics theory foundation compared with previous research methods, and the result accords with objective law and mechanics principle, and the conclusion obtained is accurate, clear and convincing. Compared with the previous research methods, the process of the damage rate evolution mathematical model established by the invention is controllable, the period is short, and the time and the costare greatly saved.