With high power density, fast charging-discharging speed and long cycling life, supercapacitors have been a kind of highly developed novel energy-storage device these years, showing growing performance and various unconventional shapes such as flexible, linear type, stretchable, self-healing, etc. Here, we proposed a rational design of an all-transparent thin film flexible supercapacitor based on oblique angle deposited NiO nanowires arrays. By integrating PET substrate, thin layer of Pt electrode, surround-finger-shape NiO nanowires film and PVA-KOH electrolyte, the as-fabricated supercapacitor has a good flexibility, transparency, and satisfactory energy-storage performance. This supercapacitor showed a high specific capacity of 8 F/cm³, high energy density of 1 mWh/cm³, a power density up to 1.5 W/cm³ and good stability during thousands of bending-recover test and charge-discharge cycles, respectively. This transparent flexible thin film supercapacitor and be used as ingenious energy storage devices for future portable and wearable electronic applications.