Objective To explore the effect of attachment wear on tooth movement in clear Aligner treatment, and to provide references for improving the efficiency of orthodontic treatment. Methods The tooth cone bean computed tomography (CBCT) scanning data were obtained, and the tooth model was established and assembled with the worn and complete attachment, respectively. When the appliance applied 2° distal torsion, 0.25 mm distal displacement, 0.1 mm depression displacement and 0.1 mm elongation displacement to the teeth, the changes of tooth displacement, periodontal ligament stress and root equivalent stress in the worn and complete attachment groups were compared. Results When the clear Aligner was used to apply distal torsion and elongation displacement to the teeth, the maximum tooth displacement decreased significantly, and the worn attachment caused the teeth to move obliquely when the distal translation and elongation displacement occurred. When the tooth was subjected to distal torsion, distal translation, depression and elongation, the maximum principal stress of periodontal ligament and the equivalent stress of tooth root decreased when the worn attachment caused the tooth to be subjected to distal torsion, distal translation, depression and elongation. Conclusions Attachment wear will affect the efficiency of tooth rotation and elongation.When the attachments are obviously worn, they should be replaced in time to ensure normal function of the attachments.