Self-healing conductive elastomers have emerged as a class of novel materials that are important for fabricating human-motion sensors, soft robots and healthcare monitoring systems. Herein, we report on a hydrogel of modified poly(γ-glutamic) acid polymer chains crosslinked by coordination complexes, which exhibits good stretchability (1375%), long-term stability (more than 40 days), and self-healing ability (99.0 ± 1.5% in 3 h). Furthermore, a "sandwich" structure composite was fabricated, which is composed of self-healing hydrogels and Au nanograin-decorated aligned multiwall carbon nanotube sheets. It possesses fast self-healing ability, a low stable electronic resistance of 10 ± 1 Ω sq-1, in the temperature range of -40-90 °C, the humidity range of 10-90%, and a stretching range up to 200%.