The Ti3C2Tx MXene was successfully etched in situ HF method and modification of glass fiber fabric with dopamine. The Ti3C2Tx / glass fiber Composites composites were prepared by the vacuum filtration, the EMI SE of the samples with different Ti3C2Tx loading were studied in frequency range of 2–18 GHz. The results show that the Ti3C2Tx nanosheets are successfully attached to the surface of the glass fiber, which improves the conductive network of the glass fiber. After the etching by in-situ HF method, the 002 peak position was moved from 9.5 ° to 6.1 °, and 104 peaks of Ti3AlC2 disappeared, and the Ti3C2Tx etching was successful; Due to the high conductivity of Ti3C2Tx and a large amount of electrons on the surface, which induces that contribute to ohmic losses with electromagnetic waves, thereby reducing electromagnetic wave energy and achieving electromagnetic shielding effect. In the frequency range of 2~18 GHz, the electromagnetic shielding performance of the Ti3C2Tx loading of 2.55 mg/cm2 is 55.1 dB, and the surface resistance was 0.95 Ω/sq; the average electromagnetic shielding showed that the absorption loss in the sample played a major role.