Manufacturing method of flood control assembly, flood control assembly and flood control dam

The invention discloses a manufacturing method of a flood control assembly, the flood control assembly and a flood control dam. The manufacturing method comprises the steps that S1, cylindrical assemblies with the hollow interiors are selected; S2, first notches and second notches are formed in the assemblies, notch grooves are formed in the joints of the first notches and the second notches, andthe first notches and the second notches are located in one faces of the assemblies; S3, the depths of the notch grooves are equal to the wall thicknesses of the assemblies and the heights of the second notches; when the outer circumferential surfaces of the two assemblies are tangent and are equal to the widths of the notch grooves; and the heights of the first notches are equal to the heights ofthe assemblies minus the depths of the notch grooves. The multiple assemblies serve as the first row of the flood control dam, the notch grooves are upward, and then the assemblies are sequentially stacked from bottom to top.