The purpose of this work is to study the processes of interfacial interactions, their influence on the piezoelectric properties in highly elastic composite structures, to establish the patterns that determine the volume-sensitive piezoelectric characteristics of composites and to create effective piezoelectric materials for hydroacoustic receiving devices. In the process of this work, the development of a method for obtaining anisotropic ferropiezoelectric ceramics, the development of methods for the preparation of perfect ceramic powders and composite materials based on thermoplastic fluoropolymers and the study of composite materials based on lead–calcium titanate were carried out. As a result of the study, the dependences of the hydrostatic parameters of the composites on the degree of filling, particle size distribution, piezoelectric anisotropy of the active phase and the elastic properties of the polymer matrix were established. Composite materials were based on ceramics of the PT–CT system and thermoplastic fluoropolymers F-2ME, F-62, F-2N with a degree of filling with a ceramic phase from 30 to 60% vol. The dependences of the hydrostatic piezoelectric moduli $g_h$ and $d_h$, and the quality factor $g_h\cdot d_h$ on the degree of filling of the composite for polymers F-62 and F-2ME with different average sizes of ceramic particles are plotted. It has been established that the maximum values $g_h$ = 119.1⋅10${}^{-3}$V⋅m/N and the quality factor $g_h\cdot d_h$ = 6074⋅10${}^{-15}$ m²/N are achieved for a polymer with a higher elastic compliance (F-62) at a degree of filling of 60% vol. and the use of granular filler.