Porous polyaniline (PANI) was prepared through an efficient and costeffective method by polymerization of aniline in the NaCl solution at room temperature.The resulting PANI provided large surface area due to its highly porous structure and the intercrossed nanorod,resulting in good electrochemical performance.The porous PANI electrodes showed a high specific capacitance of 480 F·g-1,3 times greater than that of PANI without using the NaCl solution.We also make chemically crosslinked hydrogel film for hydrogel polymer electrolyte as well as the flexible supercapacitors (SCs) with PANI.The specific capacitance of the device was 234 F·g-1 at the current density of 1 A·g-1.The energy density of the device could reach as high as 75 W·h·kg-1 while the power density was 0.5 kW·kg-1,indicating that PANI be a promising material in flexible SCs.