The polarization of high-order harmonics radiated from He driven by counter-rotating two-color laser field， which consists of a elliptically polarized fundamental field and its counter-rotating circular third harmonic pulse， are investigated by numerically solving the two-dimensional time-dependent Schrödinger equation with split operator method. The simulations show that the polarization state of harmonics can be fully controlled from circular polarization， through elliptically， to linearly polarized harmonics， by adjusting the ellipticity， intensity and phase of the fundamental field. This research is helpful for the generation of extreme utilityvehicle and X-ray sources with controllable polarization states in the experiment.