The relaxation phenomena arising from both the static-constrained stress and the cyclic variation of atmospheric temperature of Fe 59 Mn 30 Si 6 Cr 5 shape memory alloy were studied. Experimental results show that the amount of relaxation decreases with increasing initial compressive loading. The cyclic variation of atmospheric temperature has a smaller effect on the relaxation than the static-constrained stress does. The relaxation phenomenon is more obvious both in the earlier cycles and at higher cyclic heating temperatures. The static-constrained stress relaxation is ascribed to the combination and rearrangement of the stress-induced thin platelets of ɛ martensite. The contribution of cyclic heating on the stress relaxation originates from the formation of new-oriented ɛ martensite. The ɛ↔γ transformation, thermal stress and shape-recovery stress during the thermal cycling are considered to have significant influences on the formation of new-oriented ɛ martensite.