Deep learning has become the most widely used technical method in the field of computer vision. Target detection technology based on deep learning is a hot research topic. In this paper, the latest research progress of target detection technology at home and abroad are reviewed, then the advantages and disadvantages of traditional target detection methods are analyzed and summarized. Then, several target detection techniques based on deep learning and their merits and demerits are introduced. Finally, the existing problems of deep learning and the development trends are discussed.