Abstract: In view of the crack problem caused by the temperature difference between inside and outside of the rockfill concrete dam in cold region, based on the Dongzhuang second dam, the grid division and 3D modeling are carried out based on the engineering drawings, and the 3D finite element model calculation is carried out, the temperature stress field of rock-fill concrete gravity dam is simulated and analyzed, and the parameters of the dam are calibrated with the measured data. The results show that the tensile stress of the dam body presents a high level in winter, and the tensile stress mainly appears in the upper and lower surface of the dam body in winter, the internal tensile stress is obviously higher than the two sides of the dam, and the width direction of the two dam sections exceeds the allowable stress. It is suggested that deepening the short joint with four-layer finite element method can greatly improve the dam stability, and the project amount is relatively small.