ZnNb2O6 ceramics with a columbite crystal structure, is a promising candidate for application in microwave devices. In this study, ZnNb2O6 nano-powders were prepared using Nb2O5 and Zn(NO3)2 as raw materials by Pechini method. The microstructure and crystal structure of ZnNb2O6 powders were investigated systematically using X-ray powder diffraction and SEM techniques. The effect of amount of citric and ethylene on the formation of sol-gel and the particle size of ZnNb2O6 powders were also investigated using orthogonal design. Finally, the optimum process parameters for synthesis ZnNb2O6 nano-powders were obtained in this study.