Abstract: Based on the related theories of projection and cognition,this paper introduces a way to standardize the coordinates of a 3D model.During the continuous rotation of the 3D model around a vector passing through its center,the direction along which the model has the maximum projection area,can be found and defined as the Z-axis.Then by rotating the 3D model around the Z-axis,one of its orthogonal directions along which the model has its minimum projection area,is defined as the Y-axis.In this way,we can define a standardized coordinate system of the model,which is not only invariant to the object location and orientation but also robust to noise,model simplification and attacks.Our method is applicable to a wide range of objects,such as mesh models,cloud points models and other surface models.The projections of the 3D model on the three coordinate planes can be regarded as a feature descriptor for 3D model retrieval. Experimental results show that our method has a fast retrieval performance with strong robustness,but it is slightly accurate.