Abstract: Three cases of the stress distribution of a thin RCC double curvature arch dam, i. e. without upper outlets, with three upper outlets, and with three upper outlets and a horizontal beam and piers, are calculated and compared. Results show that the impact of the outlets, horizontal beam and piers on the stress distribution of the dam is local, and that the stress concentration chiefly occurs near the outlets'edge and cannot affect the lower parts of the arch dam.