Objective To evaluate the effects of orthodontic treatment on the condylar and mandibular positions of patients with class Ⅲ malocclusion in mixed dentition. Methods 32 patients with Angle class Ⅲ malocclusions in mixed dentition were chosen. They were treated with maxillary protraction and straight wire technique. Lateral cephalometric films were taken individually before and after treatment, and linear measurement were observed. Statistical analysis was performed using SPSS 16.0 software package. Results Cephalometric radiography: After treatment, SNA, ANS-Ptm, Co-y, Ar-y, Go-y, NSAr, NSGo, NSPog, ArGo’-SN, Y axia, facial angle, ANB, Wits, NA-PA were increased significantly. Co-x, Pog-y, SNB, NP-FH, AB plane angle were decreased significantly （P
