The work aims to study the microwave absorbing properties of the delaminated titanium carbide (d-Ti3C2Tx) nanosheets. Nanosheets were prepared by HCl/LiF etching and high-speed centrifugation. The phase composition of d-Ti3C2Tx was analyzed by X-ray diffraction (XRD), the morphology of d-Ti3C2Tx was analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the thickness of d-Ti3C2Tx nanosheets was measured by atomic force microscopy (AFM). The X-band electromagnetic parameters of d-Ti3C2Tx nanosheets and paraffin composites were measured by vector network analyzer (VNA). The loss sources of the composites were analyzed by Cole-Cole diagram. The absorbing properties of d-Ti3C2Tx were analyzed by calculating the electromagnetic parameters. The dielectric real and imaginary parts of d-Ti3C2Tx nanosheets and paraffin composites increased with the increase of d-Ti3C2Tx concentration and the enhancement of polarization and the expansion of conductive network were the main reasons for the increase of real and imaginary dielectric parts of composites. Cole-Cole diagram showed that there were many kinds of polarization in composite materials, namely the multiple relaxation polarization caused by defects, functional groups and interfaces. The microwave absorption performance analysis showed that the microwave absorption performance of the composites could be tuned by changing the concentration of d-Ti3C2Tx. When the filling content reached 15%, the absorbing property was the best. The minimum reflection loss was -20.1 dB at the thickness of 4 mm, and the corresponding microwave absorption bandwidth (< -10 dB) was 1.9 GHz. d-Ti3C2Tx/paraffin composites exhibit excellent microwave absorption properties. The microwave absorption properties of d-Ti3C2Tx composites can be tuned by changing the concentration of d-Ti3C2Tx.