Abstract: The flood-releasing regulation of the Three Gorges Project possesses the characteristics of high water head, large flood discharge, and diversified flood-releasing facilities. It is important issue of Three Gorges Project how to ensure the main structures and downstream safeties by safe and reasonable operation of flood- releasing facilities. By the hydraulics model tests, the hydraulics problems were studied relating to the feasible operation regulations of flood-releasing and the optimum operation regul ation was determined about the flood-releasing, that is, the gates of deep and surface outlets were opened in the means of uniformity, spacing, symmetry. The results indicated that the distribution of velocity are more uniformity in the downstream and the scouring at the side of the scour prevention wall is greatly improved. The optimum scheme has reached predicated effect.