1. A DR radiography lung contour extraction method based on fully convolutional network, comprises the steps as follows: establish the fully convolutional network structure of lung contour segmentation; conduct off-line training on the weighting parameters of the fully convolutional network; read the DR image and the weighting parameters of the fully convolutional network; input the DR image into the fully convolutional network, output the segmentation results of image through the network terminal with the network layer-by-layer feedforward and establish the lung contour in accordance with the segmentation results.