The work aims to summarize the research of conductive hydrogel in flexible wearable sensor and explore its application potential as a sensor device. The latest progress of conductive hydrogel in the field of flexible wearable sensing was summarized by consulting a large number of related literature. Four kinds of conductive hydrogels were classified according to the hydrogel network, and their design, synthesis, structure and potential applications were summarized. The factors affecting the multifunctional properties of conductive hydrogels, such as conductivity, mechanical strength, adhesion, ant-freezing, self-healing and various responsiveness, were discussed. The flexible wearable sensors with self-adhesion, ant-freezing, self-healing and other excellent properties were summarized. Conductive hydrogel is a multifunctional material with unique stimulus response, and it is of great significance to further exploration in the field of flexible wearable sensing.