As an emerging two-dimensional material, MXene is a potential nonlinear optical material. For this purpose, Nb₂C nanosheets are prepared and their absorption spectrum is measured with a spectrophotometer. Firstly, Nb₂C nanosheets are prepared by hydrofluoric acid etching and liquid phase exfoliation. Then, the morphology of Nb₂C nanosheets is characterized by scanning electron microscopy. Finally, it is discussed through experiments. Experimental results show that the micro-nano fiber device modified by MXene can achieve four-wave mixing in the communication band, and the conversion efficiency of four-wave mixing is increased by 5 dB; for a constant pump light, the wavelength range of signal light is about 4 nm; when the wavelength interval is 0.4 nm, gradually increase the amplification power of the signal light and pump light, the conversion efficiency of the four-wave mixing will gradually increase, the conversion efficiency and the incident power are linear, and the conversion efficiency does not appear to be saturated, so there is room for further improvement.