Methods, systems, and apparatus, including computer programs encoded on computer storage media, for broadcasting audio. In one aspect, the method includes receiving, from a server by a smart broadcasting device associated with a service client, an audio broadcast instruction; in response to receiving the audio broadcast instruction, downloading an audio file corresponding to the audio broadcast instruction, wherein the audio file comprises a marketing content related to services provided by the server to the service client associated with the smart broadcasting device; and broadcasting, by the smart broadcasting device, the audio file by using a speaker of the smart broadcasting device.