Abstract: To obtain ZnO nanowire array with good UV emission characteristics，it has been synthesized on p-GaN film substrate prepared by an aqueous solution route at low temperature（105 ℃），in which the diameter of the nanowires are between 100 - 300 nm. p-GaN substrate has been pretreated by three different methods respectively，the results show that the substrate which has been included in the ammonia immersion was advantageous to the growth of compact，uniform，directional ZnO nanowire array，which is closely related to OH- concentration on the surface of the p-GaN film substrate when soaking with ammonia. It indicates that the density and size of the grown nanowires depend significantly on the pretreatment of p-GaN. In addition，the ZnO nanowire array has good ultraviolet emission characteristic，which is expected to find application in the field of ultraviolet light-emitting diodes.

Key words: p-GaN film, ZnO nanowire, ammonia, pretreatment