Innocuous hydrogels with the characteristics of high conductivity, stretchability and air-stability have potential applications for emerging wearable and bio-related electronic devices. In this study, we develop a rapid and green method for stretchable supercapcitors using safer chemicals to produce hygroscopic conductive polymer hydrogels, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/poly(vinyl alcohol)/poly(methacrylic acid) (PEDOT:PSS/PVA/PMAA). The as-fabricated conductive polymer hydrogels show a high stretchability as well as a high conductivity (3.1 S cm−1) after absorbing water moisture as the plasticizer, which are used as current collectors and electrode materials to assemble the supercapacitor. By modulating the PEDOT: PSS composition in the hydrogel, the fabricated supercapacitor exhibits fascinating mechanical properties and excellent electrochemical characteristics. The supercapacitor has a maximum specific capacitance of 7.38 mF cm−2 at 10 mV/s, and shows 82% capacitance retention over 2000 charge-discharge electrochemical cycling testing at a current density of 10 mA cm−2. More importantly, the device could be stretched up to 100% strain without affecting the electrochemical performance and is well conserved after stretching 1000 times under 30% tensile strain.