Graphene oxide (GO) membranes have good separation performance, but their low water flux and poor stability need further improvement.For this reason, this paper employs a hydrothermal method to prepare reduced graphene oxide (RGO), and utilizes silicon dioxide (SiO₂) to intercalate RGO, and then prepares RGO/SiO₂ composite membranes by vacuum filtration.The results show that SiO₂ intercalation further improves the water flux without loss of rejection and stability.When SiO2 (0.05 mg/mL) is 3 mL, the pure water flux of the RGO/SiO₂ composite membrane is as high as 21.1 L/(m²·h·bar) which is about 6 times of that of the pure GO membrane, and the retention rate of Na₂SO₄ is about 83.7%.The order of rejection for different salts was R(Na₂SO₄) > R(MgSO₄) > R(NaCl) > R(MgCl₂). Therefore, the RGO/SiO₂ composite membrane has a certain potential for application in desalination.