A facile method has been developed to prepare flexible and uniform porous carbon film/Ni (PCF/Ni) double-layer structure for simply and rapidly assembling flexible electrochemical capacitor (EC). The PCF/Ni is obtained by ambient pressure chemical vapor deposition and subsequent partial etching of Ni foil. The thickness of PCF can be controlled by etching time. The PCF has a porous structure and tightly interface with Ni, resulting in a good conductivity and large surface area. The ECs based on PCF/Ni exhibits good electrical properties. Area (volumetric) capacitance of PCF/Ni electrode with PCF thickness of 0.52μm reaches 0.31mF/cm2 (5.96F/cm3) at scan rate of 50mV/s. Maximum volumetric (gravimetric) power density reaches 2.72W/cm3 (9.05kW/kg). The performance can be further improved by increasing the PCF thickness. Furthermore, the EC based on PCF/Ni has a very short time constant (~170μs) and allows for operations at high rate up to 500V/s.