Abstract: Development of a high damping copper alloy plates used in transmission system of ships is introduced and the influences of essential heat treatments on the microstructure and performance of the alloy is investigated. Results of experiments indicate that the microstructure is clear and neat twin crystals martensite after quenched at 820~850℃ and limitation at 420℃ for 12h. The twin crystals can move and slide under alternating stress which makes a contribution to function of absorbing oscillation energy to reduce noise.