Objective To measure the displacement in femoral neck fracture by three-dimensional reconstruction,reconsider the classic Garden classification and provide guidance to evaluate the severity of different types of fracture and prognosis.Methods One hundred and fifty patients with femoral neck fracture admitted between May 2012 and August 2014 were included including 23 Garden type Ⅰ fracture,30 type Ⅱ fracture,42 type Ⅲ fracture and 55 type Ⅳ fracture.Bilateral proximal femurs in all were scanned by spiral CT preoperatively.Mimics 10.01 software was used to develop the three-dimensional model by thresholding,region growing and mirror matching.Displacement of the femoral head was measured with the three-dimensional design.Results Among the six patients with incomplete Garden type Ⅰ fracture,three were verified as incomplete fracture and three complete fracture using the three-dimensional measurement technology.Femoral head displacement angle was (19.8 ± 12.5) o in impacted femoral neck fracture.In the patients with type Ⅱ,Ⅲ and Ⅳ fractures,the medial displacement of the femoral head was (7.0 ± 2.5) mm,(14.1 ± 6.8) mm and (20.4 ± 9.3) mm,the deepest point of fovea capitiswas (11.6 ±4.4)mm,(23.2 ± 11.2)mm and (30.1 ± 10.1)mm;the femoral head displacementangle was (22.1 ± 9.9) °,(31.5 ± 15.2) ° and (37.8 ± 13.5) °.Differences in dimensional displacement parameters among all types fractures were statistically significant except the comparison between type Ⅱ fracture and impacted fracture (P ＜ 0.05).Conclusions Classic Garden classification has some limitations,thus clinicians should reunderstand the femoral neck fracture and formulate more reasonable treatment protocols.Three-dimensional reconstruction provides accurate evaluation of fracture type and displacement parameters and has high clinical value.