Inherent relationship between highway landscape layout-angle and landscape picture characteristics is found out after the analysis of many highway landscape pictures. The features of highway landscape layout-angle were extracted by the method of principal components analysis, and the participants marking values were clustered using fuzzy-cluster algorithm. Then a mathematics model based on support vector machine is built up, which can be used to assess highway landscape layout objectively. The results show that it is proper to use the model based on support vector machine to assess highway landscape layout.