The poor charge separation efficiency is mainly responsible for the low photocatalytic hydrogen production performance, and the establishment of heterojunctions between phase interfaces is an important strategy to solve this problem. Here, the 2D ultrathin van der Waals (VDW) heterojunction MoC@NG@CN was synthesized by a simple electrostatic self-assembly method for improving photocatalytic hydrogen evolution under visible light irradiation. MoC acts as the active site to accelerate the surface reaction while effectively facilitating the separation of photogenerated carriers. The face-to-face contact between nitrogen-doped graphene loaded with MoC (MoC@NG) and carbon nitride (CN) provides a large number of channels for charge transport. Furthermore, the 2D ultrathin structure not only shortens the charge transfer distance but also facilitates mass transfer between photocatalysts and reactants. As a result, the optimized photocatalyst MoC@NG-70@CN shows the best photocatalytic hydrogen production activity of 2109 μmol g⁻¹ h⁻¹, which is 13.4 times higher than that of pristine CN. Our work confirms the importance of MoC@NG for enhancing the photocatalytic performance of CN and sheds light on the construction of 2D VDW heterojunction photocatalysts.