Merging a source mesh to a target mesh is one useful and important mesh operating technology. This paper introduces a method merging with mean value coordinates. The method firstly computes the mean value coordinates of the vertices in the source mesh with respect to its boundary. After specifying the difference between the two mesh's boundaries, it interpolates the difference of the source's inside vertices through the coordinates, and then constructs a new mesh to merge. With the same framework, smoothing the seaming line can be achieved by interpolating tangent vector variations. This method avoids the mesh parameterizations or the solving a large linear system, but does merge through computing close form expressions. Experiments show that mesh merging with this method is less artifacts and faster, comparing to the method through solving Poisson equation.