The determination of slope gradient for waterway dredging is related to the stability of channel dredging slope and the normal operation of the waterway,as well as the dredging engineering quantity and engineering investment,especially for shallow and deeply excavated waterway.At present,the table lookup method is still used to determine the dredging slope gradient in the specification.The value range of waterway slope gradient is given according to different rock and soil types,and it is pointed out that slope gradient of open waterway under strong wave action needs to be slowed down,but there is no specific method to consider the wave dynamic loads.Based on phase II project of 300,000-ton class waterway in Lianyungang Port,this paper introduces the design wave standard and uses the empirical formula to determine the wave dynamic load acting on the dredging slope of waterway.The vibration triaxial test is used to simulate the wave dynamic load on the dredging slope soil,obtain the soil strength index after the wave load,calculate the soil mechanical stability safety factor of the waterway slope,and form a method for determining the waterway dredging slope quantitatively considering the influence of wave dynamic load.On the basis of the general provisions of the specification,it provides useful supplements for reasonably determining the slope gradient of waterway dredging slopes.