The finite element method was used to simulate the temperature and stress fields of the ninth discharge section of the Longkaikou Roller-Compacted Concrete(RCC)gravity dam throughout the process of the construction and operation periods. The gravity load, hydrostatic pressure, temperature load, change of Young’s modulus with age, and creep effect of concrete were considered in the calculation of the stress field. The results show that high tensile stresses of 3 to 4 MPa occur near the discharge orifice in the construction period, but decreas to 2 MPa in the operation period. High tensile stress also occurs in the upper portion of the dam due to the high pouring temperature in summer and a large temperature drop after construction, but the stress state will be improved after 10 years of operation. The compression stress of the dam is less than 2 MPa, except for higher compression stress at the dam heel due to stress concentration. The stress states near the discharge orifice and in the dam body indicate that the dam is basically safe.