A modeling method of lip contours was proposed based on Principle Component Analysis (PCA). Firstly, the lip contours of 5 000 training samples were labeled, and the Procrustes analysis was performed on the coordinates gotten by labeling to normalize the data. Then the PCA was used to identify modes in data and compress the data dimension without losing the lip contour information.Furthermore, the lip contour model was constructed by using a mean value and eigenvectors gotten by PCA. Finally, the model constructed by the first 16 modes gotten by PCA was taken to reconstruct the lip contours of the original 5 000 samples. Experimental results indicate that the first 4 modes respectively describe the rotation, lower lip, scale and corners of the lip,and other modes describe more detailed lip variation.The mean difference of every feature point between the lip contour gotten by model reconstruction and the original contour is less than a width of 0.6 pixels. The model can satisfy the precision requirements of the feature location.