Objectives: To compare different effects on proclination of lower incisors. Methods: 40 AngleII/I patients , who were treated by extracting 4 premolars and preadjusted 0.022 x 0.025 edgewise appliance (MBT) ,were divided into 4 groups, marked A,B,C and D .Group A was leveled by 0.018 round stainless steel wires . Group B was leveled by 0.018 round stainless steel wires plus bite planes. Group C was leveled by 0.019x0.025 rectangular stainless steel. Group D was leveled by 0.019x0.025 rectangular stainless steel plus bite plane. Before and after leveling, lateral cephalometric radiographies were taken .The changes of proclination of lower incisors were calculated, means of changes were obtained and be used to be tested by Student—Newman—Keuls multiple range test(SNK). Results: All 4 methods leaded to increase of proclination of lower incisors. The 4 groups aligned by quantity of increase from the least to the most were :B, A, D, C. Statistical significance was found between B and C. But there were no statistical significances between other groups. Conclusions: Although statistical significances were not very obvious, present study found that compared with rectangular wires, round wires would increase the proclination of lower incisors in leveling. As an assistant leveling appliance ,the bite plane would increase proclination of lower incisors too.