Abstract: The relationship of the highway net densitywith the population density and per capita GNP in a national region is analyzed by use of the section data of three different times, and it is found that among them there exists a stable mathematical relation and a statistics law. Considering that the highway net building is influenced by the industrial structure of resources, the highway net construction policies and the other transport patterns, a concept of highway dependence-favoritism index is put forward, which is used to explain the variation between the actually obtained highway net densities and the values obtained by model calculation. This study can afford a fundamental theory for the harmony development of national highway network, population and economy.