Abstract: Physical properties of Internet are discussed in this paper. Based on giant samples, weighted Internet is firstly defined, a physical property of weighted Internet-weighted traveling diameter-is defined. And then according to features of samples, a model is put foreword. The model includes two parts: one part is logistic model, which simulates the development of traveling diameter, and the other part is sine and cosine functions, which simulates the oscillation during the development of traveling diameter. Since the development of weighted traveling diameter is very complex, the model proposed in this paper is far from suitable while being used for a long-term forecast. To solve the problem of long-term forecast, correlation dimension of weighted traveling diameter is firstly calculated, which proves that the development of weighted Internet traveling diameter is a phenomenon of chaos and a strange attractor exists. Finally, based on correlation dimension and properties of chaos path near the strange attractor, a model of four-dimension function group is put foreword, which is comparatively suitable for a long-term forecast.