Under the background of the new development of western part of China, it is important to decide how to construct western highway of China. Integrated with the present situation of western areas highway situation, in this paper, the authors forecast the suitable development scale of different classes of highway in the next years in ten western provinces by network knot-point model. Then work out the reasonable highway density of ten provinces. Through harmonious analysis of population density, national and provincial main highways and highway transport hub, the conclusion can be drawn that the forecasting density could adapt to the future demand of social economy development in western part of China.