A new horn for high displacement amplification has been designed and tested. The profile of the horn is a cubic B?zier curve. The design of the horn is based on an optimization procedure where the profile of the horn is optimized via the parameters of a cubic B?zier curve to meet the requirement of displacement amplification. Finite element analyses are carried out to obtain accurate modal frequency and displacement solutions for the proposed horn. A horn prototype has been fabricated. Based on the finite element analyses, maximum Mises stress of the proposed horn is much lower than that of the catenoidal horn. Experimental results of the harmonic response of the fabricated horn confirm the effectiveness of the design method. The experimental results show that the B?zier horn has the displacement amplification 50% larger than the catenoidal horn. The proposed horn may be more suitable than the classical stepped and catenoidal horns in application where high displacement amplification and low stress concentration are required.