A novel electrochemical non-enzymatic glucose sensor based on three-dimensional Au/MXene nanocomposites was developed. MXenes were prepared using the mild etched method, and the porous foam of Au nanoparticles was combined with the MXene by means of in situ synthesis. By controlling the mass of MXene in the synthesis process, porous foam with Au nanoparticles was obtained. The three-dimensional foam structure of nanoparticles was confirmed by scanning electron microscopy (SEM). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical performance of the Au/MXene nanocomposites. The Au/MXene nanocomposites acted as a fast redox probe for non-enzymatic glucose oxidation and showed good performance, including a high sensitivity of 22.45 μA mM−1 cm−1 and a wide linear range of 1–12 mM. Studies have shown that MXene as a catalyst-supported material is beneficial to enhance the conductivity of electrons and increase the loading rate of the catalyst materials. The foam structure with Au nanoparticles can provide a larger surface area, increase the contact area with the molecule in the catalytic reaction, and enhance the electrochemical reaction signal. In summary, this study showed that Au/MXene nanoparticles have the potential to be used in non-enzymatic glucose sensors.