To obtain the most important influence factors in road route selection quickly and effectively, we put forward a method that we call an analytic hierarchy process. In this method, we first use a matrix to show the mutual relationships of factors. We then analyze and calculate the matrix. Finally, we obtain the relative importance of all factors in the overall system. The result derived using this method is more reasonable and more directviewing to reflect influence coefficient. And based on the firsthand information of designs and the social background, the method can give qualitative indicators before program design, which prevented blindness of designing process and the designer can get more suitable road lines.