Ordered nanostructure arrangement directly from solution onto surface is one of the important methods to synthesis advanced materials. In this paper, solvent-assisted self-assembly of ZnO nanoparticles on mica was investigated. Results showed ZnO nanoparticles were closely linked to each other and formed fork-like nanostructures on mica. ZnO nanostructures were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The possible mechanism of nanoparticle self-assembly was given. The decrease of solvent density led to the aggregation of nanoparticles. It may provide a simple and effective method to construct nanostructures.