A ZnS-ZnO complex semiconductor was obtained through co-precipitation of Zn(NO3)2 in the mixed solution of Na2S and NaOH followed by calcination at 400℃ in N2 atmosphere. Due to its narrower band-Gap energy, the prepared ZnS-ZnO showed much better absorptivity for visible light than pure ZnS and ZnO. Thus, the ZnS-ZnO showed the highest activity for the photocatalytic degradation of 4-chlorocatechol (4-CC) under visible light irradation.