||Eco-friendly renewable hydrogen energy is in the spotlight due to the problem of global warming caused by carbon dioxide emitted from the use fossil fuel. Photocatalytic water splitting is an ideal method utilizing only solar energy to produce hydrogen in a clean way with no greenhouse gas emission. The candidate material as a photocatalyst is g-C3N4, which has high chemical and thermal stability and low cost. However, single g-C3N4 could not achieve best photocatalytic activities because of its fast recombination of photogenerated electron-hole pairs. To solve this problem, we synthesized WOx/g-C3N4 heterojunction with a facile two steps. The photocatalytic activities of g-C3N4 and WOx/g-C3N4 heterojuntion were evalutated with hydrogen production.