Using X-ray Photoelectron Spectroscopy (XPS) technique, the interaction mechanism between polyvinylcarbazole (PVK) and fullerene (C-60) in photoconductive PVK film doped with C-60 was studied. PVK and fullerene can form electron transfer complex according to the molar ratio of PVK unit and C-60 being about 2:1 in room temperature, and the formation and dissociation of the complex are reversible with the change of temperature. The formation of complex is the key to improve the photoconductivity of PVK.