Aiming at the problems of low recognition rate of surface defects of industrial products by traditional detection algorithms and inaccurate localization of small defects, an improved Faster RCNN deep learning network was proposed to detect defects. Firstly, after data enhancement, the traditional Faster RCNN feature extraction network is improved to make the network layer deeper to enhance the feature extraction capability of small defects. Then, the ROI Align algorithm is used to replace the rough ROI Pooling algorithm to obtain more accurate defect location information and obtain anchor frames that are more suitable for defects. Experimental results show that the recognition effect of the improved network on surface defect detection is up to 99%, which is more than 10% higher than the original Faster RCNN network, and the detection ability of small defects is also significantly improved.