Two-dimensional (2D) MXenes have attracted much attention due to their unique structural characteristics and novel performance in a variety of functions. The fabrication of 2D Ti3C2 MXene by acid etching usually requires a long period of over 10 h. In this work, we report on the rapid preparation, thermal stability and electromagnetic interference (EMI) shielding effectiveness of 2D Ti3C2 MXene. With the processing conditions optimized by adjusting the etching time and temperature, Ti3C2 MXene with a scattered accordion-like structure has been successfully achieved by etching Ti3AlC2 powders with 40% HF at 50 °C for only 0.5 h. The as-synthesized Ti3C2 was stable at temperatures up to 300 °C in air, but stable in vacuum at temperatures up to 800 °C. The as-synthesized Ti3C2 MXene has good EMI shielding performance. The total shielding effectiveness of Ti3C2 in a WAX matrix exceeded 20 dB in the whole frequency ranging from 2 to 18 GHz. The maximum shielding effectiveness value achieved to 34 dB at 18 GHz as the Ti3C2 content was up to 70 wt%. This work provides an approach for the large scale preparation of the Ti3C2 MXene.