Target acoustic scattering is the primary characteristic of target echo stealth performance, and it is an important sign of the viability of large-scale complex targets underwater. In a test band, owing to the superposition of scattered waves and the elastic echo produced by shells, liquid tanks, partition plates, ribs, etc., a target exhibits an extremely complex echo phenomenon. Accurate measurement and evaluation of the acoustic scattering characteristics of underwater complex targets can be achieved via experimental research on the echo characteristics of large-scale scaled models. In this study, the contribution and regularity of the strong reflection source of underwater complex targets in various azimuths, structures, and locations were analyzed quantitatively as a basis for in-depth research and understanding of the echo characteristics of underwater complex targets.