Graphene oxide is modified by diethylenetriamine through a one-step route to prepare GO-NH(CH2)(2)NH(CH2)(2)NH2 (GO-DETA), which has primary and secondary amino groups and carboxyl groups. GO-DETA is characterized by Fourier transform-infrared spectrum (FT-IR), X-ray diffraction spectroscopy (XRD), thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The catalytic performance of obtained GO-DETA is investigated in Knoevenagel condensation and Michael addition in water; the results show it can be used as an efficient and stable catalyst. In addition, it has other features, such as simple preparation, good recyclability and environmental friendliness. (C) 2015 Elsevier B.V. All rights reserved.