Abstract: In order to low the processing cost of exponent horn with an inner straight hole,satisfy the actual application requirements under the stress and purse the larger amplification coefficient,an exponent horn with an inner straight hole is changed into the one through bolted connection of several divided segments with holes in this paper.The frequency equation and the formula of the amplification coefficient of the modified horn are derived.Based on finite element method,distribution of the stress and the displacement along the axis of the horn are studied.The results show that under the same resonant frequency and geometrical dimension,the amplification coefficient of the modified horn is larger than the solid one,and slightly less than the one with an inner straight hole.Furthermore,the stress distribution curve is smoother.It is expected to apply to the actual ultrasonic machining.