Аннотация:Interpretation of the observations of the variable polarization of binary stellar systems and other objects requires a comparison of observed and calculated polarization curves. The description of the polarization phase curve form on the Q, U plane for the periodic linearly polarized radiation has been suggested on the basis of the Q, U Stokes parameters expansion in a Fourier series. Parameters of the ellipses for several first Fourier harmonics of X-ray binary systems optical radiation are given for some cases.