To reduce platinum usage, ultrathin MXene sheets with little restacking effect were prepared. The ultrathin MXene was prepared by a two-step etching process, which showed high specific surface area with low charge transfer resistance. The sample showed a double layer capacity of 64.98 mF cm−2, which is 14 times as large as that of ordinary HF prepared MXene, indicating a larger electrochemically active surface area. It showed a much better HER performance of ∼190 mV at 10 mA cm−2. The better performance attributes to 0.4 wt% Pt loaded. The Pt loaded MXene exhibited a better HER performance of ∼75 mV at 10 mA cm−2 and a Tafel slope of 61.7 mV·dec−1 close to 40 wt% commercial Pt/C. The sample performed better than Pt/C in a 3 h chronopotentiometry test and hardly changed in ECSA after the cyclic experiment. With more Pt loading, the sample delivered better HER performance than Pt/C in the LSV test (∼51 mV at 10 mA cm−2). This work provides an effective route for the preparation of ultrathin MXene sheets with larger electrochemically active area and more active sites for Pt loading, leading to superior HER performance.