Abstract: Objective:To investigate the effects of treatment of anterior cross-bite with functional regulator Ⅲ(FR-3).Methods:Ten patients with anterior crossbite were treated with FR-3,and the curative effects,treatment time and indications of FR-3 were analyzed.Results:The effects of treatment for 9 patients were good except one case giving up treatment because of noncooperation.The mean time of treatment was(5.41.9) months,and the recovery of close relationship and teeth chewing function returned to normal.Facial appearance of type Ⅲ turned into type Ⅰ.Conclusions:FR-3 has good effects on treating the patients with anterior crossbite during the growth and development period.