Piezoelectric single crystal composites (PSCCs) are important materials for preparing underwater acoustic transducers because of their high piezoelectric coefficients, electromechanical coupling factors and figure-of-merit. However, different types of underwater acoustic transducers have different requirements for piezoelectric materials, therefore, it is of great significance to design the structure and performances of PSCCs according to the specific application requirements of underwater acoustic transducers. In order to accurately select the parameters of piezoelectric phase and polymer phase, such as material properties, volume fraction, aspect ratio, et al, a design approach with a combination of analytical model and numerical model was proposed. Experimental results confirmed that this approach can accurately and efficiently predict the vibration modes and macroscopic equivalent performances of the 1-3 PSCCs. The present study provides a guideline from the underwater acoustic transducers to the PSCCs.