This paper reports a novel flexible optical pressure sensor based on a porous elastomer film as a light transmission medium with ultra-high sensitivity and simplicity. The pore-closing behavior under external pressure and corresponding change of light transmittance of porous elastomer film were investigated. The porous elastomer film based optical pressure sensor showed highly sensitive and stable performance with the sensitivity of 2.177 kPa-1 over the pressure range of 0-10 kPa. Finally, the optical pressure sensor was integrated with thin film solar cell to modulate the generated electrical current towards self-powered sensing platform.