The subjects of this study are the members of Kang-ning Tug-of-war Club. This study uses ankle joint flexibility and backward pulling force to discuss the effect of ankle joint flexibility training on improvement of backward pulling force. In the study, eight new female member of the club underwent ankle joint flexibility training, which including ankle joint strength training, ankle joint flexibility training, ankle joint mobility training, and their feet fulcrum condition. The pulling force, namely smaller included angle (with bent knees) and larger included angle (stretched knees) between the center of gravity and feet fulcrum, shows significant effect on the backward pulling force in eight-people tug-of-war. Appropriate planning and guidance of ankle joint flexibility training based on the characteristics of tug-of-war, under the premise of avoiding exercise injury, can effectively improve the muscular strength of the lower body and backward pulling force, as well as the exercise performance.