The development of novel photocatalyst is an important issue for improving the photocatalytic hydrogen production efficiency. Herein, novel aqueous ternary CdxMo1-xSe quantum dots (QDs) are prepared with five ratios (x = 0, 0.5, 0.67, 0.75, 1) by modulating the metal content. Experimental results show that the doping of Mo promotes the photoinduced electrons transfer and decreases the photoinduced electron-hole pairs recombination. Compared with the CdSe QDs, Cd0.75Mo0.25Se QDs, Cd0.5Mo0.5Se QDs and MoSe2 QDs, Cd0.67Mo0.33Se QDs exhibit significantly enhanced photocatalytic activity, and the amount of H-2 production comes up to 911.1 lmol in 7 h. Meanwhile, the Cd0.67Mo0.33Se QDs display substantially high stability in recycling test, which facilitates the utilization of ternary QDs in the photocatalytic hydrogen production application.