Text data Augmentation technology uses limited data to generate new samples by changing the original text content. It can effectively increase the data size of the training set, improve the generalization ability and robustness of the model, and solve the model overfitting caused by insufficient training data or uneven sample distribution. This paper proposes a data augmentation method based on a Chinese character vector. First, use the Word2vec model to obtain a Chinese character vector collection by training on the Chinese Wikipedia corpus. Second, choose a replacement character in the text that needs to be augmented. Finally, find one or more characters with the closest similarity through the character vector set to replace the words selected in step 2 to generate new samples. We mix the text in the original training set and the augmented text to form a new training set as the input of the CNN (Convolutional Neural Network) model for classification. The experimental results show that the model performance of CNN improves by 1.57% before and after using our proposed data augmentation approach. Compared to the word-level replacement data augmentation technique, our approach reduces the algorithm running time by four-fifths.