In oblique incidence, the multiple-cavity narrowband thin-film filter will have high polarization dependent loss. A novel 100 GHz angle-tuned thin-film filter with low polarization dependent loss based on the birefractance crystal polarization beam splitter is proposed. By modulating the incident angle and the polarization modes of the incident light, only the general thin-film filter can change its transmitting central wavelength. The stack of the multiple-cavity thin-film filter can be greatly simplified, and its cost will be reduced. This tunable filter has many advantages such as simple structure, low cost and low polarization dependent loss. The experiment shows that its tunable range can easily cover the whole C-band.