Replacing platinum for catalyzing hydrogen evolution reaction(HER) in acidic medium remains great challenges. Herein, we prepared few-layered Mo S2 by ball milling as an efficient catalyst for HER in acidic medium. The activity of as-prepared Mo S2 had a strong dependence on the ball milling time. Furthermore,Ketjen Black EC 300 J was added into the ball-milled Mo S2 followed by a second ball milling, and the resultant Mo S2/carbon black hybrid material showed a much higher HER activity than Mo S2 and carbon black alone.The enhanced activity of the Mo S2/carbon black hybrid material was attributed to the increased abundance of catalytic edge sites of Mo S2 and excellent electrical coupling to the underlying carbon network. Herein, we prepared few-layered Mo S2 by ball milling as an efficient catalyst for HER in acidic medium. The activity of as-prepared Mo S2 had a strong dependence on the ball milling time. Further, Ketjen Black EC 300 J was added into the ball-milled Mo S2 followed by a second ball milling, and the resulting Mo S2 / carbon black hybrid material showed a much higher HER activity than Mo S2 and carbon black alone. The enhanced activity of the Mo S2 / carbon black hybrid material was attributed to the increased abundance of catalytic edge sites of Mo S2 and excellent electrical coupling to the underlying carbon network.