Graphitied carbon-coated bimetallic FeCu nanoparticles (FeCu@C) are fabricated by one-step method for the first time. The FeCu@C as novel cocatalysts of g-C3N4 for improving visible-light photocatalystic hydrogen evolution. The FeCu@C as the cocatalyst of g-C3N4 (FeCu@C/g-C3N4 ) possess better photocatalyst activity (7.22 mu mol h(-1)) than that of Fe@C (2.51 mu mol h(-1)) and Cu@C (5.36 mu mol h(-1)) nanoparticles. The highest photocatalytic activity of FeCu@C/g-C3N4 can be attributed to the synergistic effect of the binary metals and the graphitied carbon layer. The bimetallic cocatalyst is not a simple combination of two metals, but a special electronic effect formed by the interaction between two metals. The Fe acts the catalytic activity center to capture photogenerated carries produced by g-C3N4, and agglomerates on the surface of FeCu alloys. Simultaneously, the coating of graphitied carbon layer can effectively enhance the stability of FeCu alloy and accelerate electron transfer. It is predicted that this work can provide new ideas and insights for the improvement of photocatalytic activity of semiconductors by non-precious alloy nanoparticles.