We report a watt-level passively Q-switched 2.8 μm mid-infrared multi-mode fiber laser by employing multi-layered two-dimensional MXene-Ti3C2Tx as the saturable absorber (SA). The MXene-Ti3C2Tx is fabricated by selectively etching aluminum layers in Ti3AlC2. The non-saturable loss, modulation depth, and saturable intensity of the SA at 2866 nm were measured to be 25.0%, 33.2%, and 0.043GW/cm2, respectively. The maximum average output power of the Ti3C2TxQ-switched fiber laser reached 1.09 W at 28.23% slope efficiency. The pulse repetition rate, shortest pulse width, pulse peak power, and single-pulse energy were 78.12 kHz, 1.04 μs, 13.4 W, and 13.93 μJ, respectively. This is the first demonstration of watt-level pulse generation in a mid-infrared fiber laser using low dimensional materials, to the best of our knowledge. These results indicate that the Ti3C2Tx is a reliable and superior broadband SA for high power mid-infrared pulsed laser generation.