  Via K$\ddot{a}$hker polarization we geometrically quantize free fields in the
spaces of motions, namely the space of solutions of equations of motion. We
obtain the correct results just as that given by the canonical quantization.
Since we follow the method of covariant symplectic current proposed by
Crnkovic, Witten and Zuckerman et al, the canonical commutator we obtained are
naturally invariant under proper Lorentz transformation and the discrete parity
and time transverse transformations, as well as the equations of motion.
