The present invention discloses a convolutional neural network-based image processing method and device and a mobile terminal. The method is suitable for being executed in the mobile terminal having a graphic program interface, wherein a convolutional neural network comprises a plurality of processing layers and a plurality of data layers, and the storage parameters of the data layers corresponding to the graphic program interface are stored in the mobile terminal and comprise the characteristic graph sizes, the texture transverse number and the texture longitudinal number. The method comprises the steps of taking a to-be-processed picture as the first data layer to input in the convolutional neural network; for each data layer, and according to the storage parameter, combining the plurality of characteristic graphs of the data layer into the corresponding large texture to store; for each processing layer, obtaining the large texture corresponding the previous data layer connected with the processing layer, calling the graphic program interface to carry out the rendering processing corresponding to the processing layer to generate the plurality of characteristic graphs of the next data layer.