Three-wheeled recumbent bike belongs to the special bicycle. The current market is about 10,000 per year, but its market demand is in growing trend. The purpose of this study is to design a new three-wheeled recumbent bike suspension system. By using simple parts and assembly methods, this paper achieves the basic shock effect and reduces its cost and weight. Existing suspension system is assembled by shock absorbers and spring, but its cost is high. In this study, a simple torsion springs are used to achieve the shock effect, not only reduces costs, but also reduce a lot of weight.