Molybdenum nitride (MoN) has been attracting increasing attention in recent years for the application of electrocatalytic hydrogen evolution reaction. However, the application of MoN for photocatalytic H-2 evolution has seldom been reported. Here, we report that the sample with the heterostructure between Mo2N and 2D ultrathin g-C3N4 nanosheet (CN) is fabricated via boil bathing method for the use of the visible light photo catalytic H-2 evolution. Without using any noble metal cocatalyst, the H-2 evolution rate of Mo2N/CN under visible light irradiation reaches 0.89 mu molg(-1) h(-1), which is approximate to 148 times higher than that of pure CN. The photoelectron-chemical experiments suggest that the carriers in Mo2N/CN can separate and transfer easier than those in CN due to the effect of Mo2N as the modification of CN. The combination of the Mo2N and CN represents not only a simple but also an economical and powerful method for the highly effective photocatalytic H-2 generation in the visible region.