In this work, ZnMoO4/reduced graphene oxide (ZnMoO4/RGO) composite was successfully synthesized by a facile hydrothermal method. The morphology, structure and composition of obtained composite were studied by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS) and Raman spectra. Moreover, the loading amount and releasing behavior of ZnMoO4 in the ZnMoO4/RGO composite were determined by the thermo-gravimetric analysis (TGA) and UV-vis spectrophotometer respectively. The inhibition behavior and mechanism of ZnMoO4/RGO for Q235 steel in 3.5% NaCl solution were investigated by electrochemical impedance spectroscopy (EIS) and XPS techniques. The results show that the ZnMoO4 nanoparticles are successfully incorporated into RGO sheets and the loading amount of ZnMoO4 in ZnMoO4/RGO is 91.59%. The inhibition efficiency of Q235 steel in 3.5% NaCl + ZnMoO4/RGO solution is superior to that in 3.5% NaCl solution, and increases with the extending released time. The highest inhibition efficiency can be obtained as 87.50% at 72 h. The higher inhibition efficiency in the ZnMoO4/RGO contained solution is mainly attributed to the synergy effect of RGO, MoO42- and Zn2+, which can form a protective film on the surface of Q235 steel.