Abstract: The effect of dispersion of graphene quantum dots (GQDs) in saturated calcium hydroxide solution simulating cement hydration pore fluid was investigated by absorbance test and static settlement test, and the effect of workability, mechanical properties and durability of GQDs blended mortar was studied. The absorbance test and static settling test show that GQDs has excellent dispersion stability in saturated calcium hydroxide solution, and the workability test shows that GQDs has almost no negative effect on the flowability of cement mortar. Mechanical performance tests shows that the 28 days flexural and compressive strength of GQDs increase by 12.3% and 12.5%, compared with ordinary cement mortar at the optimum dose of 0.04wt%, the seepage pressure increases by 175%, and the 120 days compressive corrosion resistance coefficient increases by 14.3%. Microstructure tests show that GQDs could improve pore size distribution, fill nano-pores and improve the compactness of cement mortar.