Cephalometric study of 30 deep-bite cases treated with extraction of four first premolars and Begg stage I appliance shows that the bite opening consists of not only intrusion of the upper and lower incisors but also extrusion of the upper and lower molars, furthermore, the lower incisors depressed more than the upper ones and the lower molars are elevated more than the upper ones. The moving type of teeth, the changing of base bone and soft tissue profile are also discussed in this article.