Impacted by the rapid development of the wearable and portable devices, the demands for excellent flexibility and high specific capacitance have highlighted an urgent need for developing flexible energy storage devices. In this paper, we prepare a porous polyvinyl alcohol (PVA)/polyaniline (PANI) composite with perfect mechanical performance (strain deformations of 696%). Due to its three-dimensional (3D) porous structure, deformation of the PANI can be avoided when the composite is bent or stretched. The electrochemical performance of the porous PVA/PANI composite can be maintained so that it holds promise for stretchable energy storage devices. As a proof of concept, an all-solid-state supercapacitor is fabricated by using the porous PVA/PANI composite and exhibits a high areal capacitance of 300.9 mF cm(-2) and long-life stability of 85% capacitance retention after 10,000 charge/discharge cycles. In particular, the supercapacitor can also withstand repeated bending and stretching with minimal effect on the electrochemical performance when no current collector is employed. The research presents a design approach of high strain porous composite and shows great promise for the development of stretchable energy storage devices. (C) 2017 Elsevier B.V. All rights reserved.