Abstract: Objectives In response to the self-generated sound interference problem in underwater acoustic transponders caused by acoustic crosstalk leakage and shell scattering, an underwater acoustic transponder scattering sound field simulation model is constructed under the finite-beam-width acoustic wave incidence condition. Methods The transmitting and receiving ends are equivalently regarded as uniformly distributed multi-point arrays. The simulated annealing algorithm is employed to optimize the array parameters and substituted into the finite element acoustic field model to achieve sound field simulation considering the directivity. Results The results show that the overall directivity distribution of an underwater acoustic transponder is jointly influenced by the transducer's directivity and the scattering from the housing. The acoustic isolation exhibits a linear relationship with the installation distance when the transducer is positioned far from the housing. The acoustic isolation undergoes complex variations with distance under the influence of elastic waves when the transducer is close to the housing. A pool experiment of the simplified cylindrical shell model was conducted. The simulation results of acoustic isolation considering directionality were consistent with the experimental values. Conclusions This method can be applied to the acoustic isolation design of underwater acoustic transponder structures.