According to the robust design method of multilayer optical coatings based on layer errors sensitivity control concept, the spectral characteristics responding to layer parameters errors are researched comparatively within three different application solutions of a high-performance thin-film polarizing beam splitter (PBS) in a novel orthogonal polarized dual-frequency laser. The inherent factor of film errors sensitivity of laser PBS is found by elaborately arranged numerical robust design experiments. A low layer errors sensitivity thin-film structure is robust designed for the high-performance laser PBS with moderate layer number and easy-manufacturable layer thicknesses. This PBS design solution is very suitable for mass production at low cost and high yield, which will play a positive role in the development, engineering and application of the orthogonal polarized dual-frequency laser.