Traditional geodesic-based Poison merging method requires time-consuming computation of rotational and scale fields, which restricts its interactive applications. This study proposed an efficient mesh merging method with reusable Laplacian operator. The method reduces problems of geometry merging, interpolation of rotational and scale fields into solving linear equations with the same Laplace matrix. It obtains eight scalar fields used in merging step by conducting Cholesky decomposition once and back substitutions several times, which is two orders of magnitude faster than the traditional geodesic-based method. To optimize the mesh nearby the merging boundary, it uses a robust method based on constrained Delaunay triangulation and discrete minimal surface. Meanwhile, it adopts reusable Laplacian operator again to merge the texture coordinates along with the geometry merging. The proposed method can handle models with complex topology and multiple boundaries, and the results are comparable to the traditional Poisson method but with much less time cost. The advantages make it capable of meeting the requirements of interactive response.