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Conductive hydrogel is considered a promising wearable sensor material. Developing flexible conductive hydrogel sensors with stretchability, adhesion, and stability remains challenging. In this study, a transparent, self‐adhesive, antifreeze, anti‐UV, stretchable, conductive, and reusable hydrogel with polyacrylamide/glycerol/gelatin/tannic acid/Fe3+ (PGGT‐Fe3+) structure is successfully constructed through a simple one‐pot polymerization method. The PGGT‐Fe3+ hydrogel is composed of dual networks of polyacrylamide and gelatin for organic cross‐linking, using water/glycerol as the dispersion medium, and incorporates a viscous substance: tannic acid, and a conductive substance: metal ions (Fe3+). Due to the introduction of the abundant amino, carboxylic acid, and hydroxyl functional groups on gelatin and tannic acid, the PGGT‐Fe3+ hydrogel exhibits excellent and repeatable adhesion capabilities on various surfaces (including glass, metal, plastic, and pigskin) with maximum adhesion strength of 98 kPa when attached to pigskin. Furthermore, based on the stable conductive network and high conductivity, the hydrogel not only exhibits strain sensitivity, fast response, and stability but also can stably collect epidermal bio signals. In conclusion, this work provides a new approach to the design and development of next‐generation multifunctional conductive hydrogels and opens up vast possibilities for their applications in the flexible electronics field. [ABSTRACT FROM AUTHOR]

[Display omitted] • An alternating layered structure of CNT and GaInCu alloy (GCLA) is proposed. • Fibers with wrinkled GCLA layer show extremely high stretchability and conductivity. • Wrinkled GCLA layer enables fiber to achieve stable conductivity during stretching. • The GCLA structure can be patterned on hydrophilic and hydrophobic substrates. Liquid metal (LM) composites, known for their excellent conductivity and fluidity, hold great promise in the fields of printed electronics and wearable technology. However, their high surface tension and fluidity can lead to circuit instability, such as leakage during deformation, resulting in short circuits. Therefore, additional methods are necessary to enhance the stability of LM within composite material systems. In this paper, Carbon nanotube (CNT) was introduced as a transition layer to enhance the adhesion of gallium-indium-copper-alloy ink (GCLA) on different elastic substrates and to obtain interface fusion conductive layers. The modified GCLA conductive fibers achieved high conductivity (conductivity up to 3.13 × 105 S/m), ultra-stretchability (1580 % of ultra-large deformation, the resistance changes less than 3 Ω), and ultra-stability (within 200 % of large deformation, the change of resistance less than 1 Ω). In addition, we also demonstrated the operability of GCLA in forming patterns on hydrophilic and hydrophobic substrate surfaces and obtained conductive patterns through printing, transfer printing, and hand drawing, making it a promising candidate for flexible electronics. [ABSTRACT FROM AUTHOR]