Ultrasonic flow measurements are carried out and analyzed for hydropower turbine units in Xiangjiaba Hydro- power Station. Based on the principle of repeatability, error analyses are performed on the repeatability of the turbine flow, unit output and guide vane opening. Using the measurement data under 14 different water heads, the actual Winter Kennedy flow coefficients are calculated and compared with those from model experiment. Then, optimal flow coeffi- cients are selected as the actual measurement flow coefficients. In the end, comparative error analysis is carried out on the calculated and measured flows.