Objective  To explore the anatomical morphology and characteristics of the sustentaculum tali based on CT three-dimensional reconstruction, so to provide anatomical support for the treatment of calcaneal fractures with screw implantation.    Methods  From March 2019 to March 2020, a total of 336 adult calcaneal CT three-dimensional reconstruction images from the Affiliated Hospital of Traditional Chinese Medicine of Southwest Medical University were collected after exclusion of inclusion criteria. The CT threedimensional reconstruction of calcaneus was classified according to the β, the prolate axial intersection between sustentaculum tali and calcaneus on the normal posterior. Reference points, β; AB, the distance from the inside of sustentaculum tali to the inside of posterior talar articular surface; AC, the distance from the inside of sustentaculum tali to the outside of posterior talar articular surface; AD, the distance from the inside of sustentaculum tali to lateral of calcaneal; AE, the distance from the inside of sustentaculum tali to medial process of calcaneal tuberosity; AF, the distance from the inside of sustentaculum tali to calcaneal tuberosity; AG, the distance from the inside of sustentaculum tali to lateral process of calconeal tuberosity. The results were statistically analyzed according to type, sex and body side.    Results  Under the β, the sustentaculum tali was classified into three types: typeⅠ(β<70°, 68 cases, 20.24%), type Ⅱ(70°≤β<80°, 153 cases, 45.54%), type Ⅲ(80°≤β<90°, 115 cases, 34.23%). For the distance of β, AB, AF, there were statistical differences between type Ⅲ and other types (P<0.05). For the distance of AE, there were statistical differences between type Ⅲ and typeⅠ(P<0.05). Meanwhile, for the distance of AB, AC, AD, AE, AF, AG, there were statistical differences between male and female (P<0.05). For the distance of  β, AB, there were statistical differences between right and left (P<0.05).    Conclusion  Under the β, the sustentaculum tali is classified into three types, with the typeⅡas the main type. When treating calcaneal fractures with internal fixation, direction of screw implant can choose between 70° to 80° as soon as possible. The morphology and classification of sustentaculum tali are of certain clinical implication to treat calcaneal fractures.