Abstract: Based on the replacement of natural sand by recycled fine aggregate from construction waste, the comprehensive physical properties and hydration mechanism of graphene oxide (GO) modified recycled cement-based composites were studied. The recycled cement-based composites were prepared by ultrasonic dispersion GO and vibration stirring. The comprehensive durability test results show that compared with recycled cement-based materials without GO, the flexural and compressive strength of the GO/recycled cement-based composites modified with 0.03% GO at 7 d age increase by 16% and 21%, respectively. The flexural strength and compressive strength of GO/recycled cement-based composites modified by 0.02% GO at 28 d age increase by 13.7% and 13.6%, respectively. The GO/recycled cement-based composite has a 7 d weather resistance and good mechanical properties after 50 freeze-thaw cycles; the chloride ion content is less than 0.06%. The radioactivity test results show that internal exposure index I_Ra and external exposure index I_r of GO/recycled cement-based composites belong to Class A building materials. The hydration mechanism of the GO/recycled cement-based composites was studied by XRD, TG-DTA, SEM and other means, the results show that GO promotes the large-scale formation of ettringite (AFt) crystals, and the presence of more free water in the gel pores, and has an inhibitory effect on the later generation of calcium hydroxide (CH), thereby improving the synthesis of GO/recycled cement-based composites physical properties.