Spot detection technology plays an important role in modern scientific research and application. Due to its advantages of high detection sensitivity, simple signal processing, and strong anti-interference ability, four-quadrant detectors have been widely used in spot detection technology and are the key components in acquisition, tracking, and pointing systems. Firstly, the spot models commonly used in spot detection and the principle of four-quadrant detector spot detection were introduced. Then, the research results of four-quadrant detector spot detection at home and abroad, as well as the factors affecting the accuracy of four-quadrant detector spot detection and the commonly-used spot detection algorithms were analyzed. The four-quadrant detector spot detection system was introduced, including the beam alignment detection system, four-quadrant detector tracking communication composite system and micro-nano laser communication system. Finally, the development prospects of spot detection technology was prospected.