Abstract: A robust 3D model digital watermarking algorithm for triangle meshes is proposed.By the algorithm firstly,the 3D model is transformed into a new one by an affine transformation,to achieve the invariance property with regard to rotation and scale.Secondly,the masking factor at each vertex based on an estimate of the averaged difference between the positions of connected vertices to the vertex is used for modification of the location of the vertices,and the strength of the watermark signal is adaptive with respect to the local geometry of the model.Experimental results show that the proposed method is not only simple in implementation but also fairly robust against common mesh attacks such as mesh simplification,mesh cropping,random noise added to the vertex coordinates.