A novel scheme ofdual-frequency Nd:YAGlaser is proposed and demonstrated. The resonant cavity of the laser contains a piece ofversatile element: crystal-quartz-made birefringent Fabry-Perot etalon, serving as both aselector and a splitter of laser axial-modes. Because of the intra-cavity birefringence,each longitudinal mode is split into two linearly and orthogonally polarized components,that is, ordinary mode (o-mode) and extra-ordinary mode (e-mode). Meanwhile due to thesame reason, the unique transmission maximum of the etalon within the overall lasingbandwidth of the Nd:YAGlaser is also split into two transmission maxima, namely, ordinary light transmissionmaximum (o-peak) and extra-ordinary light transmission maximum (e-peak). Simultaneousoperation of the two axial modes can be obtained, by making an o-mode coincide with thecentral position of the o-peak, and an e-mode with that of the e-peak. A piece ofbirefringent Fabry-Perot etalon, with a geometrical thickness of 645 micrometers and acut-angle of ten degrees between the quartz crystalline axis and the normal of itssurfaces, has been designed and fabricated. A frequency-difference of approximately twogigahertz has been obtained experimentally, when the above birefringent etalon beingplaced in a 40-millimeter-long cavity of the LD pumped Nd:YAG laser.