Abstract: Accurate head shape data are needed when designing various complicated equipments for head and face. A 3D head model can supply enough information. This paper provides a multi-layer model to reconstruct 3D human head shape. The primary data acquired from human head CT graphics and Fourier series is used to fit the border of each graphic. In order to construct a standard 3D head model by averaging a set of samples correctly, several character layers are defined. Detail method and formulas for constructing the standard 3D head model are presented in this paper. As an example, a standard model from 98 samples is built up.