Objective To evaluate the histologic changes in the dermis and the changes of the rate of type Ⅲ and type Ⅰ collagen by the radiofrequency device. Methods The effects of radiofrequency current on the dermis were observed. Ten rabbits were treated by radiofrequency, and the histologic change in the dermis were observed by H-E staining and Sirius red staining. Results After RF treatment, the fibers in the dermis appeared more compact and the quantity of the type Ⅲ (red) and type Ⅰ (green) collagen were both increased. The fibers in the dermis appeared more compact and the rate of type Ⅲ and type Ⅰ collagen was increased. It was also found that a significant proliferation of dermal collagen was observed in 8 days after treatment. As time went by, the proliferation of dermal collagen was more pronounced, and the rate of type Ⅲ was increased. Conclusion The radiofrequency current can increase the quantity of collagen in the dermis and increase the rate of type Ⅲ and type Ⅰ collagen, which may be one of the key mechanisms of facial rejuvenation by RF.