Octree representation has the advantage of being able to represent complex shapes approximately through the repetition of simple primitive shapes. Due to this reason, octree representation together with VRML(Virtual Reality Modelling Language) is usually used for approximating 3D shapes. Since the data size of octree representation increases rapidly as 3D shape to be represented is more and more complicated, its transmission time also increase. In this paper, provided is the new octree representation and encoding/decoding scheme for real-time transmission through the internet in order to visualize 3D geometric data of large size approximately.