Objective To apply spine morphology measuring instrument based on three-dimensional projection position of the spinous process on the body surface in different types of scoliosis. Methods Thirty-two adolescent idiopathic scoliosis (AIS) patients were enrolled in this study. The spine morphology measuring instrument based on space posture sensor was used to measure the spinous process angle (SPA) of the projection position on the patient back surface. Then linear regression model was used to establish the quantitative relationship between SPA and Cobb angle measured by full-spine X-ray film. Based on the Lenke classification, subgroup analysis was conducted to further explore the quantitative relationship between SPA and Cobb angle in different types of scoliosis. Results The 32 AIS patients included 11 males and 21 females, with an average age of (13.94±0.84) years; 20 cases were Lenke typeⅠ and 12 cases were Lenke typeⅤ; eight cases had main curvature of T₅-T₁₁, four cases of T₅-T₁₂, one case of T₆-T₁₁, seven cases of T₆-T₁₂, four cases of T₁₁-L₃, and eight cases of T₁₂-L₄. Linear regression analysis found that the Cobb angle had a linear relationship with the SPA in AIS patients:Cobb angle=1.128×SPA+3.724. Further subgroup analysis showed that for Lenke typeⅠ AIS patients, the quantitative relationship was:Cobb angle=1.128×SPA+3.303. Conclusion The spine morphology measuring instrument based on three-dimensional projection position of the spinous process on the body surface can be initially applied to measure the spine morphology of the thoracic scoliosis. The spatial projection position of the spinous process on the body surface is an effective anatomical reference marker for spinal morphometry.