The present study has successfully fabricated a Cu2-xSe/rGO heterojunction for the first time using an in situ hot-injection method and employed it to produce photocatalytic hydrogen. The optimal Cu2-xSe/3%rGO can achieve an efficient photocatalytic H-2 production at the rate 3123.48 mu mol g(-1) h(-1), nearly 3.46 times higher than that of the pure Cu2-xSe. The enhanced activity can be attributed to facilitated light absorption, up-regulated charge density, lower interfacial transfer resistance as well as a longer electron decay lifetime. In the meantime, the expanded specific surface area can create more active reaction sites, leading to the enhancement of photocatalytic peropeties. Besides, the mechanism of the Cu2-xSe/rGO heterojunction's hydrogen production is proposed. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.