Objective ·To analyze the anatomical structural characteristics of maxillary sinus artery (MSA) by cone-beam CT (CBCT) measurement. Methods ·The MSAs in the bilateral maxillary sinuses were observed in 1 021 patients who went to Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, for implant surgery due to dentition defect or loss. In the CBCT bone window view, the position between the MSA foramen and the bone wall at the midline of the second premolar (P2), the first molar (M1), and the second molar (M2) was measured, and the intrasinus (the artery was located below the mucosa of maxillary sinus), intraosseous (the artery was completely located in the lateral wall of maxillary sinus), and superficial (the artery was located below the periost of the lateral wall of maxillary sinus) types of their location were classified. The distance between the upper and lower edges of the MSA foramen was measured as the diameter of the artery (DMSA). The distance between the lower margin of the vessel and the sinus floor (DVSF) was measured. The lateral wall thickness of maxillary sinus and the width of maxillary sinus at 5 mm above the maxillary sinus floor at the middle line of the M1 tooth position were measured, and the angle formed by the internal and external side walls of maxillary sinus at 10 mm above the lowest point of maxillary sinus floor was measured. The differences of variability of MSA position, MSA shape type, DMSA and DVSF in patients of different genders and ages were statistically analyzed. At the same time, the correlation between DMSA and DVSF of MSA and the lateral wall thickness, width and angle of maxillary sinus were statistically analyzed. Results ·① Variability of MSA position: In the 1 021 patients, 42 patients (4.1%) had MSA located at the lateral wall of the maxillary sinus and close to the maxillary sinus floor, of which 14 patients (33.3%) had bilateral MSA, and 28 patients (66.7%) had unilateral MSA. Seven patients (0.7%) had MSA located in the alveolar bone below the maxillary sinus floor, of which 1 case (14.3%) had MSA located in the alveolar bone bilaterally, and 6 cases (85.7%) had MSA located in the alveolar bone unilaterally. ② MSA shape type: The intrasinus type accounted for 36.5%, the intraosseous type accounted for 60.4%, and the superficial type accounted for 3.1%. The proportion of intraosseous type in middle-aged patients (63.0%) was higher than that in young and elderly patients (P=0.005). ③ DMSA: DMSA was the largest in M1 tooth position, which was (1.42±0.44) mm. The DMSAs of males in P2, M1 and M2 tooth position were bigger than those of females. There was a weak positive correlation between the lateral wall thickness of maxillary sinus and DMSA in P2 and M1 tooth position (r =0.2, r =0.2). In M1 tooth position, the width and angle of maxillary sinus were weakly negatively correlated with DMSA (r =-0.1, r =-0.2). ④DVSF: DVSF decreased gradually from M2 to P2. The DVSFs of males in P2 and M2 tooth position were larger than those of females. There was a weak negative correlation between the lateral wall thickness of maxillary sinus and DVSF in M1 tooth position (r =-0.3). There was a weak negative correlation between the width of maxillary sinus and DVSF in M1 position (r =-0.1). Conclusion ·The position of MSA may vary in the alveolar bone at the maxillary sinus floor and at the alveolar bone. With the increasing of age, the shape type of MSA changes from intrasinus type to intraosseous type.Male patients have greater DMSA and greater risk of arterial bleeding than women. The larger DMSA can be observed in the thicker lateral wall of maxillary sinus, while the DMSA is smaller when the width and angle of maxillary sinus is larger. The DVSF in men is larger than that in women, and the DVSF is smaller in the thicker lateral wall of maxillary sinus or when the width of maxillary sinus is larger.