Hydrogel is a flexible material with a high water content， excellent biocompatibility， and adjustable mechanical properties， making it an ideal choice for constructing high-performance， flexible sensors. The Hofmeister effect can alter the aggregation state of hydrogel molecular chains through various ionic action mechanisms without the need for complex chemical modifications. This enables synergistic optimization of hydrogel mechanical properties and electrical conductivity， thereby meeting the need for high-sensitivity detection in complex environments. Furthermore， the Hofmeister effect opens up a novel research avenue for the development of environmentally stable hydrogel sensors. Consequently， hydrogel flexible sensors based on the Hofmeister effect demonstrate significant potential for application in the field of smart electronic devices. This review offers a comprehensive review of the mechanisms by which the Hofmeister effect regulates hydrogels， summarizing its impact on the regulation of their mechanical properties， electrical conductivity， environmental stability， and biocompatibility. Additionally， it explores the applications of hydrogel flexible sensors based on the Hofmeister effect. It is concluded that the development of hydrogel flexible sensors modulated by the Hofmeister effect is a pivotal research direction for the future， aiming to provide a theoretical foundation and practical guidance for the further advancement of hydrogel flexible strain sensors.