Vehicle detection and recognition is of great importance to the development of Intelligent Transportation System(ITS)，but Target Recognition is a challenging problem for low_resolution Radar. This paper proposes a Vehicle Recognition approach using Doppler Radar, and the spectrum variation of one vehicle reflects its outline. Then, the dimension of effective spectrum feature can be reduced by the methods of Principal Component Analysis(PCA) and Linear Discriminant Analysis(LDA), then vehicles can be classified into three types by classifier algorithms such as Support Vector Machine(SVM), k-Nearest Neighbor(KNN). At last, the paper compares the experiment results of different algorithms by cross validation, and shows the algorithm based on PCA-LDA-SVM can achieve ideal result.