Abstract: Stick-slip vibration is a typical friction-induced vibration during the service of high-speed train braking system, and the intense vibration generated will deteriorate the friction of the braking interface, exacerbate the failure of the braking structure, and threaten the braking safety. To reveal the stick-slip vibration behavior of brake system, a multi-body dynamics model of braking system considering normal multi-point contact and tangential complex friction characteristics of discs is established. The model considers the assembly relationship between brake clamps, brake pads, hanger and other core components in detail, which can reflect the stick-slip vibration behavior of high-speed train brake system and the dynamic response of brake pads and other components more accurately. Then, the correctness of the model is verified by comparing with the experimental data of the track tests. Based on this, the effects of brake disc speed, braking force and brake disc suspension stiffness on the stick-slip vibration behavior of brake system under different decay factors are studied. The results show that with the increase of brake disc speed, braking force and brake pad suspension stiffness, brake pad vibration alternates between periodic vibration and hybrid vibration. When the brake disc speed is low, the braking force is large and the brake pad suspension stiffness is small, the stick-slip vibration will induce the brake system resonance, and the two are superimposed on each other. In addition, the larger the decay factor, the smaller the chaotic region of the bifurcation diagram as well as the region of induced resonance, and the more stable the braking system. The research results can provide a new idea for the research of stick-slip vibration behavior of high-speed train braking system.