A thermoacoustic device includes a substrate, a sound wave generator and a signal device. The substrate has a net structure and includes a number of first wires and a number of second wires. The first wires and the second wires are crossed with each other. Each of the first wires includes a composite wire. The composite wire includes a carbon nanotube wire structure and a coating layer wrapping the carbon nanotube wire structure. The sound wave generator is located on a surface of the substrate and includes a carbon film. The signal input device is configured to input signals to the sound wave generator.