The piecewise approximation approach method was used to simplify the grinding wheel to cylinder.The amplitude horn was combined with grinding wheel, and the dynamic model of the whole amplitude transformer was built. The analytical solution was calculated by transfer matrix method, and the influence law of each section′s diameter and length on amplification coefficient for the whole amplitude transformer was obtained. Then， the ANSYS finite element optimization was performed.The optimized deviation reduced 4.7 Hz, amplification coefficient increased by 1.73%, and the displacement nodes moved forward 6.9 mm. Finally， the related dynamic characteristics of the whole amplitude transformer were tested, and found that ultrasonic atomization was observed when water was dripped on the output of the designed ultrasonic acoustic system. The effect of longitudinal vibration was good in continuous operation for 8 hours, and the design of non-resonant large tool head horn was realized.

ultrasonic amplitude horn; piecewise approximation approach method; non-resonant; large tool head; finite element analysis; acoustic properties measurement