Under the assumption that the parity conservation does not hold for the decay processes of strange particles, we examine both the angular distribution of the final decay product for the cascade decay of Ξ hyperon and the asymmetrical distribution of decay product about the production plane of hyperons which are produced by K- - p interaction. So far as our kinematical study for these processes is concerned, it is impossible to know whether the decay interaction is invariant under the time reversal. However, there exists a possibility of solving this problem by making use of the values of phase shifts for π-N scattering. Namely, if the two decay interactions, Ξ→Λ+ π and Λ→N + π, are invariant under the time reversal, we may expect that the fore-aft asymmetry (with respect to the direction of motion of Λ) of the final decay product for the cascade decay will be observed, while if they are simultaneously invariant under the charge conjugation, we cannot probably confirm the existence of asymmetrical angular distribution.