To study the relationship between the resistance of the submerged tooth spur dike and its backwater response，a method for calculating the drag coefficient of submerged tooth spur dike is established by using a combination of physical flume tests and theoretical analysis. The drag coefficient is mainly related to the dimensionless submergence degree and relative dam length. Furthermore，the method of conservation of momentum is used to construct the backwater prediction model of the submerged tooth spur dike which is related to the drag coefficient and backwater effect. The backwater prediction model is verified by the measured data，and the calculated results are in good agreement with the experimental data. The results can be used as a reference for the study of the drag and backwater effects of other types of spur dike or buildings involved.