The main content of this research is t o optimize the properties of window layers for large-area CIGS solar cells,and the ZnO:Al films are deposited by magnetron sputtering.The product of standard d eviation of resistivity and the transmittance is made as a uniform standard to m easure large-area ZnO window layer to confirm the best speed of substrate.Then the structural electrical and optical properties of ZnO:Al films deposited with different powr levels and pressures are investigated,and the optimum process con dition of window layer for solar cells is confirmed.The structural,electrical an d optical properties of ZnO:Al films obtained at different conditions are charac terized by means of scanning electron microscopy (SEM).Hall measurement and spec trophotometry.After comparison of the uniformities of ZnO:Al films deposited wit h different substrate speeds,4nm/s is confirmed as the best one.The lowest res istivity obtained in this study is 1.0×10－3 Ω·cm and the average tran smittance is above 85% in the wavelength range of 400－1200n m.It is found that ZnO window layer films with uniform thickness,excellent elect rical and optical properties could be obtained under improved process conditions .