During the past several years, transition metal compounds have shown high activity in the field of photocatalysis. Therefore, the MoSe2@Co3O4 with excellent photocatalytic properties through simple hydrothermal and physical mixing methods was prepared. This composite material was composed of n-type semiconductor MoSe2 and p-type semiconductor Co3O4. After optimizing the loading of Co3O4, the optimal hydrogen production can reached 7029.2 mu mol g(-1)h(-1), which was 2.34 times that of single MoSe2. In addition, some characterization methods were used to explore the hydrogen production performance of the composite catalyst under EY sensitized conditions. Among them, the UV-vis diffuse reflectance spectra suggests that MoSe2@Co3O4 exhibits stronger visible light absorption performance than the single material. Fluorescence performance and photoelectrochemical characterization experiments further prove that, the special structure formed by MoSe2 and Co3O4 and the existence of p-n heterojunction effectively accelerate the separation and transfer of carriers meanwhile inhibit the recombination probability of electron-hole pairs. Combined with other characterizations such as XRD, XPS, SEM and BET, the possible hydrogen production mechanism was proposed. (C) 2020 Elsevier Inc. All rights reserved.