Abstract: objective: to explore the influence of biomechanical characteristics of foot-ankle coupling system of badminton players on sports risk at the moment of landing, so as to provide reference basis for avoiding the risk of high-frequency and high-intensity landing of ankle joint of beginners. Methods: 60 male badminton players of Tianjin Institute of physical Education (30 of Grade 2 and 30 of beginners) were selected as the research object, the beginners as the experimental group and the players of Grade 2 or above as the control group. The Kistler three-dimensional force measuring platform and Qualisys motion capture system produced by Swedish company were used to collect the kinematic and dynamic data of each subject's ankle joint, and the average values of three effective tests were taken, and the data between the two groups were compared. Results: 1Kinematics: the angle of metatarsal flexion and dorsiflexion in the experimental group was significantly smaller than that in the control group (P < 0.05). The angles of varus and internal rotation in the experimental group were significantly larger than those in the control group, but there was no significant difference between valgus and external rotation. 2Kinetics: the left and right directional forces in the experimental group were significantly larger than those in the control group (P < 0.05), but there was no significant difference in anterior and posterior directional force and vertical force between the experimental group and the control group (P > 0.05). 3 Joint torque: the valgus moment and external rotation moment in the experimental group were significantly higher than those in the control group (P < 0.05), and the internal rotation moment in the control group was significantly higher than that in the experimental group (P < 0.05). Conclusion: compared with beginners, the ankle movement of professional athletes has good dynamic stability and flexibility, the buffer task can be completed with less range of movement and force in the left and right direction, and the angle of metatarsal flexion and dorsiflexion of professional athletes is increased. it is also the embodiment of good training effect, so that the buffer time is slightly longer to prevent the impact of sudden landing of the ankle joint. It is suggested that beginners should not only strengthen the training of the fibula muscle group. Can also be aimed at the ankle and foot and calf coordination, improve the range of movement, can effectively avoid the risk of exercise.