The helicity amplitudes for the processes of e~+e~-→J/ψ→γη_c→γY■ (Y: hyperon) are presented,together with the joint angular distributions for η_c decays into ■, Σ~0 ■~0 and ■~+■~+. The sensitivities to measure thehyperon decay parameters in these decays are evaluated based on the helicity amplitudes. The prospects to test the Bellinequality in experiment using the decay of η_c→■ are discussed. The helicity amplitudes for the processes of e ~ + e ~ → J / ψ → γη_c → γY ■ (Y: hyperon) are presented, together with the joint angular distributions for η_c decays into ■, Σ ~ 0 ■ ~ 0 and ■ ~ + ■ ~ +. The sensitivities to measure thehyperon decay parameters in these decays are evaluated based on the helicity amplitudes. The prospects to test the Bellinequality in experiment using the decay of η_c → ■ are discussed.