The shape memory ability, microstructure and crystal structure in Cu-21.30Zn-5. 36Al(wt.%) shape memory alloy have been extensively studied as a function of thermal cycling. Crystal structure of quenched alloy is M18R(β₁`) martensite, and it become fragmentary with increasing thermal cycles. Shape memory ability is decreased and stress-induced 2H(γ₁`) martensite and residual parent (DO₃) phase are founded during thermal cycling. Reversible shape memory effect is occurred according to thermal cycling at 473K, in which martensite plate, only 18R structure, is occurred incorporation and intersection.