To evaluate the change of the the face type and the cant of the occlusal plane of the patients with Angle Class Ⅱ, division 2 before and after orthodontic treatment, in order provide evidence for clinical treatment.

In 30 patients with Angle Class Ⅱ, division 2, 4 first premolars were extracted. They were treated with straight wire appliance. Pre-treatment and post-treatment lateral cephalograms of the patients were obtained and evaluated. Seven parameters including AOP-FH, POP-FH, OP-dif, MP-FH, N-Me, N-ANS, ANS-Me were selected and analyzed.

There were significant differences in AOP-FH, N-Me, POP-FH and ANS-Me (P＜0.05), while there were no significant differences in other parameters.

After the straight wire appliance treatment for Angle Class Ⅱ division 2 patients, heights of 1/3 lower face increases, both anterior and posterior occlusal plane decreases, especially the anterior occlusal plane.