To study the influence of different graphene sound-generator structures on thermoacoustic efficiency, a sound pressure analytical model was established. Theoretical and experimental studies were conducted on the thermoacoustic efficiency of a monolayer graphene sound-generator, multilayer graphene sound-generator, and nickel/chromium-based graphene foam sound-generator. Firstly, the principle of a graphene sound-generator was introduced. A periodic temperature change model and a sound pressure analytical model of this generator were then established. Finally, the three aforementioned sound-generators were studied using an experimental method. The experimental results show that the maximum SPL values of the monolayer, multilayer, and the graphene foam sound-generator are 35.19, 20.36 and 33.42 dB, respectively, in the frequency range of 14~25 kHz when 6 V AC is applied for a distance of 6 cm. The maximum theoretical SPL is approximately 37.45 dB. Graphene sound-generators with lower resistance, lower specific heat capacity, and higher thermal conductivity can achieve higher thermoacoustic efficiency and sound pressure.