The frame structure design is the core link in the manufacture of electric-assisted bicycles. It not only determines the basic performance of electric-assisted bicycles, but also directly affects the comfort and safety of riders. As the skeleton of the bicycle, the frame carries the weight of the entire vehicle and connects various components, so the rationality of its design is very important; the choice of materials is also a very important step. The frame made of different materials brings The riding experience is also different.