The present invention provides a facial expression recognition feature extraction method employing edge detection and SIFT. The method comprises: acquiring an image containing a face; dividing the image into a background class and an object class, and performing edge detection to obtain a sub-image about face information, i.e., an object class sub-image; and extracting a feature point in the object class sub-image, and generating a SIFT descriptor for expression information in the object class sub-image. In the invention, the effects of a background on important information are eliminated during a feature extraction process, a SIFT descriptor is obtained by performing feature point extraction on an image, and the extraction process is extremely stable with regards to noise, illumination, partial occlusion, and affine transformation. A SIFT descriptor in an image is extracted to complete image matching and PCA is used for dimensionality reduction, thereby speeding up feature extraction and matching, and improving the efficiency and accuracy of matching. The invention is applicable to image recognition, image face recognition, and image comparison.