CdS films were prepared with chemical pyrolysis deposition (CPD) at different temperature followed by annealing. The results of microanalyses show that the prepared CdS films were dense and uniform and that their average grain sizes varied for different growth temperature. The CdS films deposited at 400-450℃ were poly-crystalline with wurtzite phase structure, and its lattice constants are: a=4.135 and c=6.713 Å. Hall measurements on electrical properties at room temperature show that resistivity, carrier density and mobility of the non-annealed CdS poly-crystalline films deposited at 400℃ were 1.48×104Ωcm, 1.82×1011cm-3 and2.42×103 cm2/(V s), respectively. The electrical properties of CdS films can be improved by annealing at a certain temperature range if these films are used as optical windows for solar cell.