This paper analyzes the spectral reflection properties of skin surface with make-up foundation. Foundations with different material compositions are painted on a bio-skin. First we show the limitations of the previous models used for describing the complicated reflectance curves by a small number of parameters. A new approach based on PCA is then proposed for describing the detailed shape of surface-spectral reflectance. All skin surfaces exhibit the property of the standard dichromatic reflection, so that the observed reflectances are represented by only two spectral components of a constant reflectance and a diffuse reflectance. Moreover, the weighting coefficients are decomposed into two basis functions with a single parameter. Thus, the spectral reflectance at arbitrary angular conditions can be estimated by synthesizing the diffuse spectral reflectance and several one-dimensional basis functions. Finally, the feasibility of the proposed method is examined using many skin samples with different material compositions of make-up foundation.