In recent years, tremendous efforts have been devoted to develop new photocatalyst with wide spectrum response for H2 generation from water or aqueous solution. In this paper, MnxCd1-xS composites were in-situ fabricated via the high-temperature sulfurization to enhance the solar-light photocatalytic capacity of H2 evolution. Benefiting from the S defects and junction interface between MnS and CdS, MnxCd1-xS composites exhibited the better H2 evolution rate than pure MnS. The H2 evolution rate of optimal Mn0.5Cd0.5S with a Mn(II) content of 22.52% and a Mn/Cd mole ratio of 0.95:1 was 9.27 mmol g−1 h−1, which was 35.65 and 2.38 times higher than pure MnS (0.26 mmol g−1 h−1) and CdS (3.89 mmol g−1 h−1), respectively. In addition, H2 evolution capacity of Mn0.5Cd0.5S decreased from 44.83 to 41.66 mmol g−1 after three cycles. Mn0.5Cd0.5S prepared via the high-temperature sulfurization was thus a potential material for solar-light induced H2 generation.