The design versatility and performance advantages render supercapacitors (SCs) the highly appealing candidates for the energy storage units in flexible devices. For this purpose, a flexible electrode with high capacitance and excellent mechanical stability is essential. Herein, the facile fabrication strategy towards flexible SC electrodes with polyaniline (PANI) nanowires loading on nitrogen-doped carbon coated SS mesh (PANI/N-C/SS) is developed via a simple hydrothermal carbonization process and the following deposition of PANI. Derived from glucose and dicyandiamide, the nitrogen-doped carbon layer can effectively improve the contract of the SS substrate and PANI. The resultant PANI/N-C/SS electrode delivers a high areal capacitance of 624mFcm−2 at 0.05mAcm−2. With a large size of 40cm2, the solid-state symmetric capacitor based on PANI/N-C/SS still possesses a capacitance of 122.6mFcm−2, corresponding to a high energy density of 0.22mWhcm−2.