Objective: To explore the effect of attachment wear on tooth movement in clear aligner treatment, and to provide reference for improving the efficiency of orthodontic treatment. Methods: The tooth scanning data were obtained by CBCT, and then the tooth model was obtained by mimics,Geomagic and assembled with worn and unworn attachments. finally, ANSYS was used to analyze the changes of tooth displacement, periodontal ligament stress and root equivalent stress after clear aligner applied force. Results: 1. When the clear aligner was used to apply distal torsion force and crown displacement force to the teeth, the maximum tooth displacement decreased significantly. 2. The worn attachment causes the tooth to tilt when the crown displacement occurs. 3. When the tooth is subjected to distal torsion, distal translation, root displacement and crown displacement, the maximum principal stress of periodontal ligament and root equivalent stress are reduced. Conclusion: the wear of attachment will affect the efficiency of tooth movement, and the influence of wear factors on the efficiency should be taken into account in the design.