Objective To investigate the assessment of patients with functional ankle instability prior to and post of regular rehabilitation therapies. Methods One hundred and twenty-four patients with unilateral chronic ankle instability (51 females and 73 males, age 34-56) were received conventional rehabilitation for two month, including muscle strength, range of joint motion, balance, proprioception, etc. The visual analogue scale（VAS）scores (instant pain and pain after 500-meter walk ) were recorded. Standing time of affected limb, the star excursion balance test, static and dynamic plantar pressure were performed. Results There were significant differences in VAS pain score of instant pain(5.32±0.27 vs 1.07±0.08) and after 500 meter walk (8.79±1.78 vs 4.51±1.78) (P<0.05), and standing time of affected limb and the star excursion balance test between the data after and before training. In contrast, no significant difference was observed in the groups of static and dynamic plantar pressure. Static: normal anterior foot（1095.30±61.28）gr/cm² vs（1670.30±151.22）gr/cm²; Dynamic: normal anterior foot（1654.98±294.27）gr/cm² vs affected limb（2822.30±312.28）gr/cm² (P > 0.05). Conclusion Rehabilitation therapy can significantly improve the pain-release, the balance, etc. However, the effect on the dynamic response is not accurate. Thus, the abnormal of walking posture, the biomechanics of the foot and ankle, and biomechanics of functional ankle instability should be considered during the rehabilitation treatment.