In this report, a metal-semiconductor-metal (MSM) ultraviolet photodetector based on ZnO nanofiber film with Au electrodes was demonstrated. The ZnO nanofibers were synthesized via effective electrospinning process and characterized by means of XRD, SEM, XPS, and UV-visible absorption spectra. At 5V bias, the dark current of the device was 17.8nA. Under the irradiation of 260nm ultraviolet light, the photocurrent could reach 11.5A and a high responsivity of 790A/W was achieved due to the large internal gain. The mechanism of the high internal photoconductive gain was discussed in the article. The experiment presented a general and simple approach to integrate electrospun nanomaterials into photodevices directly.