Abstract: As a one-dimensional sensor, yarn-based flexible strain sensor has good flexibility, braidability and stretchability, which makes it have great application advantages in human motion monitoring. The preparation methods of yarn-based flexible strain sensors mainly include filature method, spinning method, finishing method and composite method, and the preparation process and research progress of various yarn-based flexible strain sensors are expounded from the preparation method, and the characteristics, advantages and disadvantages of various preparation methods are summarized, and finally the future research direction of yarn-based flexible strain sensors is proposed, which provides a reference for further preparation and research of such sensors.