In this thesis, we have investigated the approximate chiral invariance of the strong interactions within the context of the flavor mixing. Assuming that the chiral invariance is broken by the introduction of the weak interactions, we have established in the six quark model a relationship among the chiral symmetry-breaking parameters, the flavor mixing angles and the quark mass ratios. The implication of the $U_A$(1) symmetry on the flavor mixing has been also investigated. We have found that it may provide the group-theoretical explanation for the discrete symmetries of the phase transformation type upon the Higgs interaction Lagrangian.