Abstract: Room-temperature synthesis of ZnS was controlled at the oil-water liquid-liquid interface. Combining with polymer films which were modified by hydroxyl-terminated self-assembled monolayers(SAMs) as flexible substrates,nanocrystalline ZnS films were fabricated on the substrates. X-ray diffraction analysis indicates that the ZnS films have a hexagonal wurtzite structure,which is the high-temperature polymorph of sphalerite. Scanning electron microscopy and transmission electron microscopy observations show that the ZnS films consist of nanoparticles with the diameter of 30-50 nm. Photocatalytic degradation of methyl orange by these products under UV-light irradiation was observed,which confirmed the photocatalytic degradation ability of the nanocrystalline ZnS films to organics. In view of the results,a facile one-step method,combining the oil-water interface with the SAMs-modified substrate,was proposed for fabricating the wurtzite ZnS functional films without any additive at room temperature. The relationship between photocatalytic performance and the morphology of the products was also discussed.