Objective To observe the morphology of maxillary sinus floor septa using cone beam computed tomography (CBCT), and to analyze its relationships with gender, age, and maxillary sinus volume. Methods Totally 375 patients (750 maxillary sinuses) who underwent CBCT were retrospectively selected from Department of Stomatology of The First Affiliated Hospital of Naval Medical University (Second Military Medical University).The DICOM file data of CBCT images were fed into Mimics 22.0 software to reconstruct 3-dimensional images of maxillary sinuses, and the occurrence, position, and height of maxillary sinus floor septa were observed and the volume of maxillary sinus was measured.The relationships of the maxillary sinus floor septum incidence with gender, age, and maxillary sinus volume were analyzed. Results Of the 750 maxillary sinuses 130 showed sinus floor septa, with incidence of 17.3%.The incidence rates of maxillary sinus floor septa in males and females were 18.5% (63/340) and 16.3% (67/410), respectively, with no significant difference (P=0.431).The incidence rates of maxillary sinus floor septa in the age groups of 18-30 years, 31-45 years, 46-60 years, and ＞60 years were 12.7% (29/228), 16.5% (32/194), 23.1% (36/156), and 19.2% (33/172), respectively, with no significant difference (P=0.058).The incidence rates of maxillary sinus floor septa in the groups with maxillary sinus volumes of 0-10 cm³, 11-20 cm³, and ＞20 cm³ were 7.1% (14/196), 19.9% (54/271), and 21.9% (62/283), respectively, with a significant difference (P=0.001).A total of 168 maxillary sinus floor septa were detected, of which 24 (14.3%) were located in the anterior part of the maxillary sinus, 84 (50.0%) in the middle part, and 60 (35.7%) in the posterior part.The heights of the maxillary sinus floor septa in the anterior, middle, and posterior parts of the maxillary sinus were (5.75±1.84), (9.08±3.77), and (6.41±1.76) mm, respectively, with a significant difference (P＜0.001). Conclusion The detection rate of maxillary sinus floor septa increases with the expansion of the maxillary sinus volume.CBCT can provide accurate information about the position and size of the maxillary sinus floor septa, providing a basis for clinical maxillary sinus floor elevation surgery.