From the viewpoints of both qualitative and quantitative analysis of the impact on regional economy, the externality of freeway qualitative from transport infrastructure, by increasing the scale of the transportation infrastructure, promote the development of the region's economic infrastructure construction, enhance the capacity of traffic supply, further enhance regional economic agglomeration effect, speed up regional manufacturing and circulation of elements. The quantitative model mainly starts from two aspects. The first model analysis is the enterprise input-occupation output model. By reflecting highway resources, ecological environment and other factors, the role of highway on the sustainable development of society and "economic health" is evaluated, and its external attributes are quantified. The second model uses Granger causality test to analyze the causality relationship between expressway and national economic growth. Finally, the influence of the external characteristics of the highway operation environment is deeply analyzed, and the corresponding policies and measures are formulated for different periods, the deficiencies are analyzed, and the future is prospected.