Traditional target detection algorithms based on deep learning usually require extensive computing resources and long-term training, which do not meet the needs of the industry. Lightweight target detection networks sacrifice part of the detection accuracy in exchange for faster inference speed and lighter models. They are suitable for applications in edge-computing devices and have received widespread attention. This study introduces lightweight technologies commonly used to compress and accelerate models, classifies and analyzes the structural principles of lightweight backbone networks, and evaluates their practical impact on YOLOv5s. Finally, the prospects and challenges of lightweight target-detection algorithms are discussed.