Abstract: Conductive hydrogels have great potential applications in flexible wearable devices, electronic skin and biological electrodes. However, the complex and changing application scenarios put forward higher requirements on the stretchability, self-healable, self-adhesive and biocompatibility of conductive hydrogels. In this paper, a conductive composite hydrogel (OCAPS/PAA-Na) with high extensibility, self-healable, self-adhesive and excellent biocompatibility was designed by the non-covalent cross-linking between a water-soluble polyhedral oligomeric silsesquioxane (POSS) and sodium polyacrylate (PAA-Na). The elongation at break of OCAPS/PAA-Na hydrogel is 2537.0%-4056.1%. The addition of POSS improves the mechanical properties of hydrogels: The tensile strength increases from 10.5 kPa to 23.8 kPa; The tensile modulus increases from 7.1 kPa to 27.8 kPa; The fracture energy increases from 3.7 kJ·m⁻² to 6.8 kJ·m⁻². OCAPS/PAA-Na hydrogel has excellent self-healable property, and the self-healable efficiency is up to 97.8%. The hydrogel shows good adhesion to both organic and inorganic materials, with the highest adhesive strength of 19.6 kPa and 18.2 kPa, respectively. Cytotoxicity test and hemolysis test show that the hydrogel has excellent biocompatibility. The conductivity of the hydrogel increases from 0.165 to 0.290 S·m⁻¹ with NaCl crystals is generated in situ during the preparation. OCAPS/PAA-Na hydrogel can be used as a strain resistance sensor material to accurately detect some subtle human actions and the gauge factor value can reach 5.17, which has a good application prospect in the field of flexible intelligent wearable devices and electronic skin.