Abstract: A tunable erbium-doped fiber laser based on acousto-optic tunable filter is introduced. According to the rate equation and transfers equations applicable to the erbium-doped fiber amplifier, the output formula of the acousto-optic tunable erbium-doped fiber laser was deduced. The dependence of the tunable range of acousto-optical tunable erbium-doped fiber ring laser on the amplification bandwidth of erbium-doped fiber amplifier was obtained. In the experiment, the tunable range from 1526.05nm to 1560.63nm was achieved. The experiments show that the tunable range obtained from acousto-optical tunable erbium-doped fiber ring laser is consistent with the theoretically calculated one.