The invention relates to the technical field of data processing, in particular to a CT image data automatic classification method and device based on CNN and GAN, and the method comprises the following steps: S1, obtaining CT image data to be classified; S2, selecting an image of the nodule to carry out data enhancement processing to obtain a public expansion data set; S3, obtaining a generation network and an identification network for the public expansion data set by using the GAN, and performing training at the same time to obtain a GAN synthesis data set; and S4, classifying the GAN synthetic data set by using a CNN network to obtain a final image data set. According to the method, the problem that most of existing researches about lung adenocarcinoma classification focus on radiomicsfeature modeling and other manual marking features, which are based on manual labeling, thus more burden problems are brought to doctors can be solved; according to the invention, the lightweight CNNmodel is also convenient to arrange in a hospital diagnosis system, daily work of radiologists is facilitated, development of precision medical treatment is promoted, and the invention has a very strong market application prospect.