The invention relates to a facial expression image recognition method based on an expert system. According to the method, inference and recognition of the facial expression of a preprocessed image are carried out through the expert system established on the basis of an expression image processing method and the function of a traditional computer program. The method comprises the following steps: (1) capturing an image in a video, acquiring user information in the video, then carrying out identity verification through image processing and image characteristic extraction, acquiring characteristic parameters of the expression image of a user, determining a user expression library, and establishing the expert system for facial expression recognition; (2) carrying out imaging processing and image characteristic extraction on the image captured in the video, acquiring the characteristic parameters generated when the degree of the expression of the user is maximized, comparing the characteristic parameters with parameters, determined in the step (1), of image training samples in the user expression library, and finally outputting the statistical result of facial expression recognition through an inference engine of the expert system. Compared with the prior art, the method has the advantages of being high in recognition speed and the like.