Small and monodisperse ZnS hollow nanospheres with outer diameter ranging from 60 to 70 nm and wall thickness of 15-20 nm were fabricated in a large scale by a simple surfactant polyethylene glycol (PEG) assisted method. The diameter and the wall thickness of the hollow nanospheres could be controlled by manipulating the amount of PEG and the aging time, respectively. Moreover, the wall of these hollow nanospheres is very compact. The product was characterized by X-ray power diffraction (XRD), transmission electron microscopy (TEM), UV-vis spectrum and fluorescence spectroscopy. The photocatalytic activity of as-prepared ZnS hollow nanospheres was also evaluated by using methyl orange (MO) as a model organic compound and the result revealed that their photocatalytic activity is a little lower than that of Degussa P25 TiO(2) but better than that of ZnS nanocrystals prepared by literature method. Furthermore, a rational mechanism to the formation and evolution of the products is proposed.