This paper proposes a novel continuous variable coherent optical communication mode. In this mode, two quadrature Stokes parameters are regarded as observed physical quantity, and single linearly polarized component is used as carrier wave. At the sending end, electro-optical amplitude modulator (EOM) of 45° azimuth is used to indirectly complete the linear modulation of S2 component, and S3 component is changed by continuously rotating a half-wave plate (HWP). The receiving end adopts the mode of Q-Q-H wave plate are rotated to select the component of measured S2 or S3. The circuit of balance homodyne detection is designed, and the detection system is built by combination with LabVIEW to complete signal demodulation. New optical path scheme is verified by both theory and experiment.