Disclosed is a playback system including a master device and slave devices. The master device executes the following steps: selecting data for playback; obtaining the position information of the slave devices through a wireless positioning technique; ascertaining a distribution pattern according to the position information; comparing the distribution pattern with at least a part of the patterns of multiple predetermined modes and thereby selecting one from the predetermined modes as a playback mode; and determining the playback parameters of the slave devices according to the position information and the playback mode, or notifying the slave devices of their playback roles based on the playback mode and the position information to let the slave devices determine their own playback parameters. Each slave device includes a wireless communication circuit available to the wireless positioning technique, and the slave devices play synchronously according to the master device's control.