Abstract: Rubber dams are widely employed for urban river and canal impoundment. They are the preferred water - retaining structures in water supply projects of small and medium-sized cities. Previous studies have predominantly concentrated on the stress and deformation characteristics of single-anchored dams, employing tabular methods to design geometric dimensions and tensile forces. Double-anchored lines are more commonly used in practical engineering. However, the engineering design method is not perfect. This study establishes a fluid-structure interaction theoretical model for these dams, the accuracy of the theoretical model is verified by model tests. The effects of anchor line distances, perimeters, and internal water heads on the cross-sectional shape and tension force are analyzed. Results indicate that increasing internal water head causes the ultimate external water level, cross-sectional area, and tension force to increase nonlinearly, while the dam width decreases nonlinearly. Increasing the perimeter results in nonlinear increases in ultimate external water level, dam width, cross-sectional area, with minimal impact on tension force. A simplified design equation is derived by fitting the geometric dimensions and tensile forces under design conditions using a dual-exponential growth curve model.