Purpose <p>Temporomandibular joint (TMJ) prosthesis implantation is an effective procedure for treating temporomandibular joint disorders. Traditionally, preoperative planning for TMJ surgery has been conducted manually by experienced surgeons, which often results in longer operating time and less reliable prosthesis placement. This study proposes an automated surgical planning algorithm for TMJ prosthesis implantation that calculates the optimal position for prosthesis placement.</p> Methods <p>Firstly, the STL model of the patient's craniomaxillofacial structure is populated with a point cloud, and the oriented bounding box is calculated. Next, the point cloud that meets specific constraints is filtered based on the characteristics of the anatomical structures. Subsequently, the contact surfaces of the prosthesis with the zygomatic arch and the mandible are generated according to the distribution of the point cloud. Finally, a system of linear equations is established based on the geometric constraints and solved to determine the precise placement position and orientation of the prosthesis.</p> Results <p>A group of 12 patients with 24 clinical cases was utilized for automatic planning to evaluate the efficiency and quality of the system. The results demonstrated that the average time required for the automatic planning algorithm was under 30&#xa0;s for the entire procedure. Furthermore, the calculation of the bone-prosthesis contact area indicated that the quality of the automatic planning is comparable to that of plans created by professional surgeons.</p> Conclusions <p>Compared to the cumbersome manual planning methods currently used for TMJ prosthesis implantation, the approach proposed in this paper facilitates efficient and accurate automated preoperative planning. This method simulates the optimal placement of TMJ prosthesis to ensure long-term stability, demonstrating significant clinical potential for future applications in TMJ prosthesis implantation surgery.</p>