A free-space optical hybrid is provided. The free-space optical hybrid includes a polarizing beam splitter that split the light beams S and L into horizontal polarization light beams Sx, Lx and orthogonal polarization light beams Sy, Ly, respectively, at least one birefringent crystal splits the horizontal polarization light beams Sx, Lx and orthogonal polarization light beams Sy, Ly into light beams Sxo, Sxe, Lxo, Lxe, Syo, Sye, Lyo, Lye, a light combiner that combine the light beams Sxo+Lxo, Sxo−Lxo, Sxe+jLxe, Sxe−jLxe, Syo+Lyo, Syo−Lyo, Sye+jLye, Sye−jLye and output the light beams at ports. The present invention can realize an optical hybrid in free-space by using a birefringent crystal and can split light beams of different polarization statuses in free-space well. The optical hybrid offers a compact structure and good stability.