Based on a statistical model of dam displacement, the form of hydration heat component was proposed to quantify the influence of hydration heat on dam displacement. According to the data of dam displacement, water level and dam body thermometer, the statistical model of dam displacement was established by using backward elimination-partial least square (BE-PLS) method. The displacement component caused by temperature was separated from the measured displacement data. Then, the periodic term was used as the expression of environmental temperature component, and the approximate solution of one-dimensional heat conduction equation was used to construct the model of hydration heat component. The two terms were used to fit the temperature displacement component to realize quantitative analysis of the influence of hydration heat on dam displacement. Calculation of an engineering case shows that the statistical model established by BE-PLS can effectively overcome the influence of multicollinearity among various factor variables on the fitting accuracy of the model. The proposed formula of hydration heat component is applicable, and the dam displacement caused by residual hydration heat should not be ignored.