With 5,10,15,20-meso-tetra(4-carboxyphenyl)porphyrin (TCPP) and cuprous oxide nanosheet as main reactants, a novel composite (TCPP/Cu2O) was prepared via a facile method. The assembly mechanism of TCPP and Cu2O was investigated by UV-vis spectroscopy and FTIR. The results indicated that not only peripheries of TCPP but also the central of TCPP macrocycle interacted with Cu2O Furthermore, with the obtained composite as the photocatalyst, the photocatalytic activity for hydrogen production was investigated. The composite showed more excellent performance for hydrogen production than that of Cu2O composite. By means of fluorescence spectra, electrochemical impedance spectra and photoelectronic performance measurement, the mechanism of electron transfer in the composite was explored. The results showed that the introduction of TCPP can enhance the light absorption of Cu2O, and the strong interaction between TCPP and Cu2O can quicken the transfer of photo-generated electrons. It hoped that this work can open up a new perspective for the assembly and application of dye-functionalized semiconductor nanoparticles. (C) 2017 Elsevier B.V. All rights reserved.