Abstract: In order to obtain a composite horn with large amplitude ratio,the method of optimization design has been introduced.Taking the composite exponential solid horn with a conical section at the narrow end as an example,under the condition of given resonant frequency and the large section and small section diameter of the horn,the resonant length as the design variable,the resonant frequency as the state variable,and the amplification coefficient can be regarded as objective function to optimize with APDL language.According to the optimization design of the best set,the results show that the finite element optimization result is the same as that of the traditional analytic method,and the maximum amplification coefficient under the given condition can be obtained.This paper provides a feasible approach to optimizing the design of the horn.