ZnO nanoparticles and Zn/ZnO core/shell structured nanoparticles are synthesized by ablating zinc target in deionized water and sodium dodecyl sulfate (SDS) solutions, respectively, using pulsed laser ablation with 532 nm pulsed infrared laser. The microstructures and photoluminescence properties of the products are characterized by X-ray diffraction, transmission electron microscopy, ultraviolet-visible and PL spectrophotometer. The formation mechanism of ZnO and Zn/ZnO nanoparticles is discussed. The results show that the mean diameters of ZnO nanoparticles are 43 nm and 19 nm, respectively, after ablating the zinc target for 2 and 4 hours in deionized water. The longer-time ablation may lead to the interaction of the ablating laser beam with the ZnO nanoparticles, resulting in the decrease of the mean diameter of ZnO. Zn/ZnO core/shell structured nanoparticles can be obtained in 0.005 mol/L SDS solution due to the enwrapping of SDS to the Zn nanoparticles. A blue photoluminescence at about 450 nm (2.76 eV) and a green one at about 558 nm (2.22 eV) are observed for the colloidal solutions of ZnO and Zn/ZnO nanoparticles.