A g-C3N4-Cu2O was successfully synthesized in the presence of PEG-400 surfactant via a hydrothermal method and high-temperature calcination method. Based on the results of TEM, XPS, EPR, and other techniques, it was verified that a heterojunction was formed. The synthesized g-C3N4-Cu2O show excellent photocatalytic activity and stability was confirmed through cycling experiments, XRD and XPS. At a suitable addition amount, the value of band gap of g-C3N4-Cu2O is reduced to 1.87 eV, the PL intensity decreases effectively, the specific surface area is increased to 12.8114 m(2)/g, and the photocatalytic degradation rate is increased to 94%. Adding the surfactant PEG-400 in the precursor solutions leads to a reduction in the crystallite size, which can improve the morphology and specific surface area to form abundant heterojunction interfaces as channels for photo-generated carrier separation, and improve its light utilization and quantum efficiency. (C) 2018 Elsevier Inc. All rights reserved.