Atomically multilayered two-dimensional transition-metal carbides have abundant interfaces, and are very promising as outstanding electromagnetic absorbing materials at thin thickness. Here, a Ti3C2Tx MXene was prepared by hydrofluoric acid etching method, and has typical multilayered morphology with stacks of nanosheets. The microwave dielectric behaviours of the Ti3C2Tx with efficient microwave absorption were investigated. The Ti3C2Tx presents good impedance matching, achieved with effective absorption bandwidth covering from 12.4 GHz to 17.1 GHz, with thickness of only 1.5 mm, which nearly covers the whole Ku band. The microwave absorption performance was adjusted, and the Ti3C2Tx has a minimum reflection loss of -34.4 dB at 12 GHz at only 1.7 mm. This study demonstrates the real potential of Ti3C2Tx MXene materials as electromagnetic wave thin broadband absorbers.