Abstract: Electrochemical sensors, as a kind of traditional sensors, have the advantages of high efficiency, good responsiveness, and high sensitivity. Flexible electrochemical sensors with these characteristics are widely used in healthcare, environmental monitoring, and food safety by virtue of their excellent flexibility, stretchability, foldability, and electrochemical stability. In addition, these sensors are featured with easy portability, lower cost, high sensitivity, and good selectivity. Based on the selection of active materials for flexible sensors, proceeding from inorganic materials, organic materials, enzymes, and natural materials, this paper analyses and summarizes the research results in recent years, introduces the influence of material selection on the performance of electrochemical sensors, primary focuses lie in the preparation and application of different materials in flexible electrochemical sensors, and shows that flexible electrochemical sensors play an irreplaceable role in production and life. Finally, this paper conclude the problems and challenges in the current research applications of flexible electrochemical sensors, and the future development of flexible electrochemical sensors are prospected.