The ZnO and 1%, 2% copper doped ZnO nano particles were synthesized, by using the chemical precipitation method. The resulting nano particles were characterized by X-ray diffraction, scanning electron microscopy, UV visible spectroscopy. Photo catalytic degradation of methyl orange in aqueous solution by ZnO and Copper doped ZnO under UVC (464 nm) irradiation was studied. The Scherrer equation for X-ray diffraction spectra was used to determine the crystallite sizes of ZnO and Cu-ZnO nano particles. The average crystallite size of un-doped ZnO was found to be 21.65 nm, while the crystallite sizes of 1% and 2% were 31.64 nm and 29.39 nm respectively. Effect of catalyst dosage, initial concentration of methyl orange on the degradation rate constant were also studied, effect of copper doping on degradation and in addition reusability aspects of nano particles where also studied which revalue’s that reused nano particles exhibited same results as that of virgin particles.