The invention provides a face expression recognition method based on a convolution neural network, which relates to the technical field of face expression recognition. At first, the method collects facial expression pictures and downloads the FER-2013 face database and CK + face database; the images are divided into a training set and a test set, then the collected images are preprocessed to obtain the 96*96 size gray-scale images, and the convolution neural network model is established; the training set is used for training and the error between the actual output result of training and the label value is calculated, and the difference value is transmitted from top to bottom through the back propagation algorithm, and the weight value is updated by the weight value update formula. After the training, the network model is saved, the image of the test set is inputted into the training model, and the recognition rate is calculated. In the invention, the face expression recognition methodis improved, the convergence speed of the model is improved, the recognition efficiency is improved, the accuracy rate of the convolution neural network is changed, and the face expression recognitionefficiency is improved to a certain extent.