A method for making thermoacoustic device includes following steps. A substrate having a first surface and second surface is provided. The first surface defines a plurality of grids. Grooves are formed on each of the plurality of grids. A first electrode and a second electrode are formed on each grid. The first electrode is spaced from the second electrode. One of the grooves is located between the first electrode and the second electrode. A number of carbon nanotube wires are applied on the first surface and electrically connected to the first electrode and the second electrode. A thermoacoustic device array is formed on the substrate by separating the carbon nanotube wires. A number of thermoacoustic device is formed by cutting the substrate according to the grids.