3D object fusion provides an easy way to generate novel models from two or more existing geometric models by using 3D cutting and pasting operations. As a new kind of geometric modeling tool, it is now attracting much more attention. In this paper, a new montage mesh fusion method based on variational interpolating implicit surfaces is proposed. The approach first calculates mesh regions to be fused by cutting original meshes with boundless planes, then constructs a variational implicit surface by interpolating mesh regions to be fused and polygonalizes the implicit surface to obtain a blending surface between/among original meshes to be fused. Smooth mesh fusion is finally obtained by cutting away unwanted portions of the blending surface and performing topology merging operations. Compared with current methods that fuse mesh objects by directly connecting mesh regions to be fused, this approach has the advantages of no restriction on topologies of the mesh regions to be fused, and thus enabling the fusion among multiple objects, fast running speed with robustness, and easiness to use. The approach shows a promising future in applications for geometry modeling as well as computer animation.