The invention discloses a medical image lung nodule detection method based on an anti-network, which mainly solves the problem of low detection precision due to shading on medical image lung nodules in the prior art. The method comprises the steps of: 1) preprocessing a medical image to acquire a sample data set; 2) scaling and cutting the sample data set, and adding Gaussian noise to all processed samples to form an expanded sample data set; 3) superimposing a Faster-RCNN detector with an anti-space discarding network (ASDN) to construct a novel detector based on the anti-network; 4) trainingthe novel detector with the sample data set to obtain a trained novel detection model; and 5) performing lung nodule detection on a test data set with the trained detection model to obtain a lung nodule detection result in each medical image. The method improves the detection precision of medical image lung nodules and can be used in a computer aided diagnosis system.