With the development of ecological irrigation area at present, it requires higher detection and control of weeds in irrigation area.In this paper, aiming at the ecological irrigation area, a classification method of weeds based on convolutional neural network(CNN) is proposed.By collecting 3 kinds of weeds and 3 kinds of crops as data sets,through cutting, rotating and so on, data is transported to the CNN.Finally, 6 categories of classifications are implemented.