Photoresponse of large-area multi-walled carbon nanotube (MWCNT) films is explored under laser illumination. The experiment shows that the photo-induced current shows nearly linear response to the bias voltage. The photocurrent depends on the laser illumination spot position, with the maximum photocurrent occurring at the metal–film interface, while the minimum photocurrent is observed between two electrodes. We are attributing this photo-generated exciton due to Schottky junction between Al electrodes and the CNTs, and electron's concentration effect. The sample device shows photo responsibility of 521 mA/W at a bias voltage of 2V, which indicates that this device can be developed as a position-sensitive photodetector.