In order to meet the requirements of adaptive optics laser guide star system, the appropriate film material is selected base on film theory. The film system′s evaluation funciton which is associated with the electric field is established by using needle optimization algorithm. The film is optimized to meet the requirements and has a lower electric field intensity distribution. Electron beam heating evaporation and ion-assisted deposition system are adopted for film preparation. The polarizing beam splitter meets the requirements of polarization coupling splitting system, and passes the environmental testing, which has a high laser damage threshold.