Abstract: Due to the lack of research on the development rule of early age mechanical properties of new and old concrete joint faces, the strength of the joint face is generally considered to be the same as that of pouring blocks, which leads to large mutual restraint of new and old concrete on the intermittent surface, and further causes a relatively large stress calculation value in the pouring block. In this paper, an experiment is designed to test the early-age shear stiffness of new and old concrete joint faces, and the required parameter duration curve is obtained. Then the test results are applied to the simulation of temperature field and stress field during the construction period of the actual concrete dams. The results show that when the joint face elements considering the early age strength development are set on the intermittent surface, the constraint condition of new and old concrete joint faces can be reasonably simulated. The calculated tensile stress of the pouring block is relatively small, which is more in line with the actual phenomenon.