Objective To investigate the effect of expanding midpalatal suture in adults by personalized miniscrew⁃assisted rapid palatal expander on condylar position. Methods Ten adult patients with maxillary trans⁃ verse deficiency were expanded using a personalized miniscrew⁃assisted rapid palatal expander. The relative posi⁃ tion parameters of temple mandible joint were measured and contrasted before expansion（T0），after expansion （T1）and after retention for three months（T2）on CBCT. A statistical analysis was completed with the SPSS 21.0 software. Results The superior space（SS），posterior space（PS）and lateral space（LS）of temple mandible joint became wider and the medial space（MS）became smaller after rapid expanding of midpalatal suture，suggesting there were statistic differences（P < 0.05），which maintained the same changes after expansion for three months， whereas there were no statistical significances in radius of temple mandible joint and horizontal angle of condyle on both sides（P > 0.05）. Conclusions Expanding midpalatal suture in adults by personalized miniscrew ⁃assisted rapid palatal expander can cause bilateral condyle position an appropriate antero⁃inferior change，which is benefi⁃cial to the stability of correction results.