Addressing the demand for elastomers with high sound absorption coefficients in underwater target acoustic absorption coatings, this study investigated the synthesis processes of polyurethane elastomers, interpenetrating polymer network (IPN) elastomers, and polyurethane-modified epoxy-based bead-reinforced sound absorbers. Small-scale tests were conducted using an acoustic tube to investigate the influence of material parameters on sound absorption performance. The test results indicate: Polyurethane elastomer samples cured at 110 °C exhibit superior sound absorption properties. A higher content of chain extender MOCA favors microphase separation, enhancing low-frequency sound absorption performance. The network topology of IPN elastomers improves damping and sound absorption capabilities. Low-density epoxy-based bead-reinforced sound absorbers using the 593 curing agent exhibit higher reactivity, enhancing viscoelastic sound absorption properties. Larger diameters of filled hollow glass beads result in higher reflection and better low-frequency sound absorption, while smaller diameters yield better high-frequency sound absorption. Polyurethane-modified epoxy-based bead-reinforced sound absorbers exhibit lower reflection and superior sound absorption performance when the material mass ratio is approximately 1:1.