In order to more accurately judge the loss of hydration heat inside the mass concrete during the casting process, a formula for the prediction of temperature distribution at the worst moment between surface and interior of concretes was established by considering six influencing factors, including the concrete adiabatic temperature rise, ambient temperature, casting temperature, heat dispersion coefficient of formwork material, heat dispersion coefficient of thermal insulation material and thickness of the casting layer. A damage calculation method of hydration heat was established based on the calibrated parameter from response surface analysis method, temperature distribution and Loland damage model, and then was verified by the finite element numerical model. The results show that the hydration heat damage equation can determine whether the damage cracking will be caused by temperature gradient at any point during the casting process.