Abstract. ZnO nanoparticles were fabricated by anodization method. Different fabrication conditions, including pH buffers (sodium hydroxide, citric acid, oxalic acid, hydrogen peroxide), electrolyte concentration, temperature and voltage were investigated. The field emission scanning electron microscopes (FESEMs) revealed that zinc oxide nanoparticles with discal morphology were formed. The optimum conditions for fabrication of nano ZnO material with discal shape nanoparticles are 1wt% NH 4 F electrolyte in water ethano(1:1) solution at 25 o C and 40v with 0.2M citric acid as pH buffer. This ZnO material shows rather high photocatalytic reduction activity of CO 2 and the yield of CH 4 reaches 2.48 umol/g catalyst. Keywords: Zinc oxide nanoparticles, discal morphology, preparation conditions, photocatalytic reduction 1Introduction Zinc oxide has drawn considerable attention because of its attractive optical-electrical characteristics [1,2] that make it potentially applicable in a lot of fields such as ultraviolet lasing [3], photocatalysts [4]and so on [5,6]. In addition, 1D nanoscale ZnO is preferred in photoanode applications due to its larger surface area [7].Anodic oxidation has been employed in synthesis of many kinds of metal oxides with 1D nanostructure [8~10]. Research on anodization of various valve metals by P. Schmuki group [11~14] showed that anodizing can be applied to the preparation of nanostructures of other valve metals. Anodization of Znthat is one of the valve metals especially synthesis of 1D nanoscale of ZnO by anodizing has been widely investigated, since its gentle conditions and cheap equipment. S. Sreekantan et al. [7] have reported that nanoneedle, nanoflower and nanoflake of ZnO can be obtained by anodization in different concentration of sodium hydroxide. Apiked ZnO nanowire structures [15] are achieved by changing the NH 4 F concentration. Studies on the preparation of ZnO strips have been conducted by Sung Joong Kim et al [16].Although many researches have concentrated on 1D nanoscale ZnO, research of various nanostructures in this field is still at primary stage. Hence, the new morphology and application of ZnO nanoparticle is yet to be further found. The key to nanostructure of ZnO