In this paper, we present a novel digital watermark system frameworkfor 3D mesh model with all mesh attributes, including position coordinates, normal, color and texture coordinates etc. Within this framework, 3D mesh model attributes are considered as geometry signals defined on mesh surfaces. A planar parameterization algorithm, which is first proposed by us, is used to map 3D mesh models to 2D parametric meshes. Geometric signals are then transformed into 2D signals. Then a wavelet-based watermark casting scheme is proposed to embed the watermark into some wavelet coefficients. Experimental results show that the embedded watermark is robust against various geometry signal processing.