The interrelation between the effective weak interaction and the hyperon structure is discussed with the aim of explaining non-leptonic decays of hyperon~ A consistent model is found by assuming that J:and A-hyperons are bound states of [ KN] with I= 1 and 0, respectively, and that the effective Hamiltonian is given solely by the phenomenological kaon interactions, K---+rc, 2rc, with IJ/1 = 1/2. This model leads naturally to the consequences: a 17 D-=::-aA-and az+-=::a 17 --=::0, which are consistent with the experiments. Derivation of this model from the field theory of composite particles is given by the covariant new Tamm-Dancoff approach. Extending our theory to the E decay, it is suggested that theE-hyperon is a superposed state of the configurations [KJ:] and [KA]. Finally, comparing the p-wave transition rates of .4-decay with that of A, the co-existence of D-and F-type strong interactions defined by SU 3 -symmetric theory is shown to be necessary.