ZnS and Zn(OH)2 capped ZnS semiconductor quantum dots (QDs) have been synthesized by the colloidal chemicalmethod using inorganic reagents. Transmission electron microscopy·and electron diffraction results have shownthat the monodispersed ZnS QDs have a diameter of 1-5nm and the wurtzite structure. The polarities of the precursors and surfactant solvents have shown strong effects on the properties of the photoluminescence for ZnSQDs. For ZnS QDs capped with a wider band gap Zn(OH)2 shell, the surface trap states were passivated andhence the band-edge emissions have been enhanced.