This paper introduces the phenomenon of self-similar network, and then it gives the mathematical definition of self-similar and analysis for the network performance. Based on this, this paper puts forward a new mapping model of ON / OFF and the chaotic mapping model based on the ideas. The model simplifies the chaotic mapping function mapping model by choosing a random variable with a linear piecewise function. The model length is subject to the state heavy-tailed. This model can capture network traffic self-similarity.