Abstract: The performance of underwater weak signal detection can be effectively improved by concentrating the underwater sound energy using the localization effect of interface states. A topology optimization method for underwater acoustic concentrators based on heterostructure waveguides is proposed. The specific method represents the waveguide structure with a matrix, combines the improved adaptive binary particle swarm algorithm, and considers the maximum acoustic pressure amplitude near the interface of heterostructures as a fitness function. The topology optimization method is used to excite an interface state with strong localization effect at the objective frequency to increase the sound wave amplitude in the region near the interface of heterostructures, and effectively enhance the underwater sound energy concentration effect. Compared with the traditional manual experience adjustment method, the topology optimization method is more efficient in the design of underwater acoustic concentrators, with a stronger localization effect of the wave energy and a gain of more than 20 dB.