Abstract: Generally, the traditional methods for designing horns, such as analytical or equivalent circuit approaches, involve large computational load and complex calculations. LTspice is employed for the design and optimization of horns in this paper. Taking a three-section composite horn as an example, the resonant frequency is calculated using the analytical method. A LTspice model is then constructed, and the horn’s section lengths are adjusted to maximize the amplification factor as the optimization goal. The resonant frequency, amplification factor, and displacement curve are calculated as performance parameters and compared with finite element simulation results for verification. The results indicate that the amplification factor increased by 11.3% after optimization using the LTspice method, and by 9.9% using the finite element method. The LTspice method provides a clear, physically meaningful, and straightforward calculation process for designing the electro-mechanical equivalent model of horns.