In order to improve the accuracy of the traditional SSD algorithm for small target detection, an improved SSD target detection algorithm is proposed: ResNet50 based on deformable convolution is used as the feature extraction network of the SSD algorithm to improve the processing ability of the target; the feature pyramid (FPN) to fuse feature maps of different layers and enrich the semantic information of shallow feature maps; introduce channel attention mechanism during feature fusion, extract corresponding channel weights, increase the proportion of important information, and improve the detection effect. Finally, the PASCAL-VOC2007 open source data set was used for simulation experiments, and compared with the traditional SSD target detection algorithm, the accuracy is significantly improved, which verifies the effectiveness of the algorithm for small target detection.