Finally, we discussed the number recognition based on Hopfield neural network. BP (back propagation) neural network can also carry out corresponding number recognition, such as handwritten number identification. Because of the characteristics of BP neural system network, the Internet must have some templates to practice, detect and authenticate the Internet. This time, we will not repeat the number recognition, but key scientific research is based on the data fitting of BP neural network. The neural network used in this application is the BP neural network, which is a double-layer positive feedback Internet used for deviation back propagation practice. The key includes the key input layer, the hide layer and the output layer. Data information is provided by