The invention relates to a thermoacoustic modular device, which makes use of the surplus heat of an aluminum cell. The invention adopts a modular structure and is formed by connecting a resonant cavity (1), a hot-end interchanger (2), a regenerator (3), a cold-end interchanger (4), a sound-wave guide tube (5) with an acoustic energy output device (6) in sequence, that is, the hot-end interchanger(2) is connected with one side of the regenerator (3), and the other side of the regenerator (3) is connected with the cold-end interchanger (4). The hot-end interchanger (2), the regenerator (3) andthe cold-end interchanger (4) are all arranged inside the inner cavity of the resonant cavity (1). One side of the outlet of the cold-end interchanger (4) of the resonant cavity (1) is connected withthe sound-wave guide tube (5) through a conical interim, and the other section of the sound-wave guide tube (5) is connected with the acoustic energy output device (6). The invention makes full use of the thermoacoustic effect and can convert the surplus heat into the acoustic power and then utilize the acoustic power to cause the surplus heat generated by an aluminum electrobath to be converted in energy through the thermoacoustic modular device, thereby improving the effective energy utilization efficiency and lowering the comprehensive energy consumption of the aluminum electrobath. The invention is simple to be manufactured and convenient to be processed and installed.