Some formulas now insue cannot correctly predict sediment transport rate at Yichang Station of Yangtze River. This paper statistically analyzed 246 sets of the observed data from 1959 to 1964 and 1973 to 1974 at Yichang station,and regarded sand bed load as uniform sand.Based on the analysis of the forces acting on the grain particle and sediment rolling incipient model,the calculation formula for incipient velocity of sand bed-load was established.The coefficient K in the formula varies with the discharge and follows the exponential distribution.In the meantime, the formulas of sand bed-load transport rate were established.The formulas were verified by the observed data of Yichang station in 1975.Calculated values according to the formulas were in good agreement with the observed data.
