ZnO nanoparticles with very narrow size distribution were synthesized by coupling homogeneous precipi-tation with microemulsion under pulsed microwave heating. The conditions of preparing ZnO nanoparticles were inves-tigated. The products were characterized with DTA, TGA, XRD, TEM and UV-Vis. The synthesized ZnO nanopartices had much stronger ultraviolet absorptivity than normal ZnO powders; the average size of products was sensitive to the variation of the power or duration of microwave irradiation. ZnO nanoparticles with very narrow size distribution were synthesized by coupling homogeneous precipi-tation with microemulsion under pulsed microwave heating. The conditions of preparing ZnO nanoparticles were inves- tigated. The products were characterized with DTA, TGA, XRD, TEM and UV-Vis. The synthesized ZnO nanopartices had much stronger ultraviolet absorptivity than normal ZnO powders; the average size of products was sensitive to the variation of the power or duration of microwave irradiation.