A high peak power actively Q-switched mid-infrared fiber laser at 2.8 μm was demonstrated with a repetition rate of 1~10 kHz by employing a 975 nm laser-diode to pump a piece of heavily Er3+-doped ZBLAN double-clad fiber and a mechanical chopper into the cavity as the Q-switch. Stable Q-switched laser pulse with a maximum pulse energy of 134.5 μJ, pulse duration of 127.3 ns and peak power of 1.1 kW was obtained at a repetition rate of 10 kHz under a proper pump power.