Nano-CdS-polythiourethane (PTU) composite particles (CdS-PTU) are prepared via making nano-CdS in a reverse micellar system, followed by surface-modification with thiol molecules, and polymerization (polyaddition) of hexamethylene diisocyanate (HDI) and dithiols (xylene-alpha,alpha＇-dithiol: XDT) or 4-hydroxythiophenol (HTP) in the presence of the surface-modified nano-CdS, The effects of thiols used as the surface-modification agent and polymerizing monomer (XDT or HTP) on stability of CdS-PTU for photo-irradiation during photocatalytic H-2 generation from aqueous solution of 2-propanol are investigated. The composite containing nano-CdS more dispersed exhibits improved photocatalytic properties, which are found to have been effected by employing benzyl mercaptan as the surface-modification agent for nano-CdS, and HTP as the monomer.