Objective To study the effect of vibration training with adjusted frequency on changes in explosive force of lower limbs, balance and muscle function around ankle joints of patients with functional ankle instability (FAI), so as to provide an empirical basis for rehabilitation training of FAI patients in clinic. Methods Twenty-six FAI patients were randomly divided into the experimental group (n=14) and the control group (n=12). The experimental group received 8-week rehabilitation training with vibration intervention, while the control group only received 8-week rehabilitation training. Changes in maximum power, average power, maximum speed and average speed of the injured limb during vertical jump with single leg, changes in distances during long jump, changes in time during one-leg standing with eyes open and closed，changes in contract time (tc), relax time (tr) and displacement (Dm) of medial gastrocnemius (GM), lateral gastrocnemius (GL) and tibialis anterior (TA) muscles before and after training were measured and compared. Results In the experimental group, the maximum power and maximum speed of the injured limb during vertical jump with single leg, the distance during long jump with single leg and the time during one-leg standing with open and closed eyes were significantly improved, and the increase was higher than that of the control group. The increase of tc of all muscles in the experimental group was smaller than that of the control group, but tr and Dm did not show any regularity. Conclusions Vibration training with adjusted frequency can effectively improve the explosive force and balance ability of lower limbs of FAI patients, and promote the tc shortening of GL, GM and TA muscles, but whether vibration training with adjusted frequency can reduce muscle tension and promote muscle relaxation is still not clear.