The invention discloses a trademark detection method based on a convolutional neural network. According to the method, various kinds of trademark pictures and pictures without trademarks are collected, and the pictures with the trademarks are marked; the convolutional neural network is initialized and is trained through trademark samples and non-trademark samples. In the picture testing process, candidate windows which may contain the trademarks in pictures to be tested are selected through a target area selection method, and color space conversion and scaling processing are carried out on the candidate windows; then the candidate windows are input into the convolutional neural network for recognition, and the candidate windows which are recognized to be the trademarks are marked in the pictures to be tested. According to the method, target area characteristic extraction and recognition are combined through the convolutional neural network, uncertainty caused by characteristic design is avoided, besides, good invariability is maintained during rotation, translation and scale changing, detection speed is increased Based on selection of the divided target area, and meanwhile the false detection rate is lowered.