The invention discloses a single image fine rain removal method based on a depth convolutional neural network. Firstly, through carrying out background texture structure extraction, nonlinear mapping and rain line area restoration on an inputted rain graph by an initial rain removal network, an initial clear rain-free image is finally obtained; the initial clear rain-free image and the original image are inputted to a fine rain removal network with a single convolutional layer at the same time, more details in the background area are thus restored, and a high-definition rain removal image is finally obtained. Through adopting a caffe framework, the initial rain removal network and the fine rain removal network are trained, parameters of each convolutional layer are obtained precisely, fine rain removal processing is carried out on a rain image, and compared with the traditional convolutional neural network rain removal method, the method of the invention can obtain a higher-quality rain-free image, the practicability is strong, and the method can be widely applied to more scenes.