A decorative structure includes at least one hollow modeling shell and at least one limiting ring. The modeling shell is assembled by two corresponding half bodies. An outside of one half body corresponds to an inside of the other half body thereby the two half bodies are positioned in the same direction. The modeling shell has at least one connecting portion along jointed ends of the two half bodies. The limiting ring surrounds an outside of the connecting portion for supporting the modeling shell. Accordingly, the present invention positions the two half bodies in the same direction so that the modeling shell is positioned before being assembled to reduce its volume.