CdS thin films prepared by vaccum evaperation have been studied the characteristcs of room temperature of scanning electron microscoe(SEM), X-ray diffraction(XRD), energy dispersive X-ray(EDX), and photoluminescence(PL)spectra. The cubic to hexagonal structure phase transitin has been determined to be $350^{circ}C~450^{circ}C$. The results of compensated donor levels of $O_2$and Si impurites at S-vacancy were identified CdO and $Cd_2SiO_4$defects. The edge emission peaks measured by PL of room temperature was donor level accoding the theses $O_2$and Si impurites were due to 2.43eV($350^{circ}C$) and 2.42eV(55$0^{circ}C$) peak energies respectively. The structure transition annealing temperature was measured $370^{circ}C$ similar to Ariza-Calderons result, $374^{circ}C$ by CBD films.