OBJECTIVE To evaluate the clinical effect of Forsus appliance in the treatment of patients with Class II malocclusion after growth spurts. METHODS Twenty-two patients with Class IImalocclusion were treated with Fursus appliance.Cephalogram pre-and post-treatment was taken,and the clinical effect was evaluated.SPASS14.0 software package was used for paired t test. RESULTS Six to eight months after treatment, SNB increased (1.4±0.002)°,overbite and overjet decreased (5±0.000) mm and (5.5±0.000) mm, the relationship of molar reached ClassⅠ, upper incisiors were retruded (1.5±0.004)°, while low incisiors were proclined (1.3±0.005)°. Significant difference was found before and after treatment (P<0.05). CONCLUSIONS The growth of mandible was promoted remarkably by Forsus appliance following growth spurts, the relationship of molar and profile were also improved.