Abstract: The effect of sodium lignosulfonate (MN) on the dispersion ability of graphene oxide (GO) in simulated cement hydration pore solution was studied, and the effect of MN-dispersed GO on the impermeability of cementitious capillary crystalline waterproofing (CCCW) was studied. The results of absorbance test, Zeta potential and atomic force microscope (AFM) show that GO has the best dispersion in saturated calcium hydroxide solution when the mass ratio of MN and GO is 3:1. The mechanical strength test of mortar shows that when the GO content is 0.03% of the cement mass, the flexural and compressive strength of 3 days and 28 days are increased by 39.13% and 39.37%, 33.84% and 33.48%, respectively, compared with the GO mortar without MN. The impermeability pressure and chloride ion diffusion coefficient of mortar are 160.0% and 50.6% higher than those of standard mortar specimens, respectively. The impermeability test shows that when the GO content is 0.03% of the cement mass, the impermeability pressure of the GO modified CCCW coating is 116.7% higher than that of the CCCW coating. Micro-test shows that GO promotes the hydration reaction, plays a filling role and template role in the mortar matrix, enhances the density of hydration products, and increases the impermeability of mortar and CCCW. This study provides a GO modified CCCW to improve the impermeability of cement mortar, and its application value in coating waterproof effect and reducing CCCW material cost is improved.