Abstract: Co₄₁Ni₃₃Al₂₆ alloy ribbons with a thickness about 0.2mm were fabricated by hot rolling and cold rolling processes.After heattreated at 1350℃ for 5 hours and then water quenched, the structure of the ribbons matrix phase converted to bamboo-liked recrystallized large grains.Martensitic transformation and damping capacity of Co₄₁Ni₃₃Al₂₆ alloy ribbons were investigated by means of differential scanning calorimetry (DSC) and dynamic mechanical spectroscopy (DMS) separately.It was found that the martensitic transformation temperature of 0.2mm thickness ribbons is about 45℃ higher than that of 1.5mm thickness plate.During cooling process, there is a damping peak appearing at the temperature from 140℃ to 25℃ which is obviously wider than its martensitic transformation temperature (121~78℃) measured by means of DSC.It is suggestsed that some stress-induced martensitic transformations took place.The damping capacity of Co₄₁Ni₃₃Al₂₆ alloy ribbon is over 0.04 corresponding to a wide temperature range, indicating that the alloy is a new kind of promising damping material.