The presence of a highly alkaline environment or large amounts of Ca2+ in concrete exerts a great influence on the dispersion of graphene oxide (GO) particles. Therefore, the development of a highly efficient GO dispersant to adapt to complex concrete environments is important. In this work, novel phosphate-modified small molecular polydentate polymers were synthesized and used as efficient dispersants for cement and high-concentration GO solutions. The chemical structure of the polymers was confirmed by H-1 NMR and IR spectroscopy, and the effect of adsorption groups on the adsorption ability of polymers was studied by using adsorption experiments and theoretical calculations. Results showed that the dispersant inositol hexaphosphate-methoxy polyether (IHP-MP) features a high adsorption equilibrium constant and strong adsorption ability. IHP-MP exhibited not only good water-reducing and slump-retaining properties but also remarkable cement hydration-retarding effects due to its numerous phosphate groups. IHP-MP could be used as an auxiliary GO dispersant with the comb polymer PCE to effectively reduce the viscosity and improve the stability of GO solutions. SEM, TGA and IR characterization indicated that IHP-MP strongly interacts with the surface groups of GO particles. Graphic