Through surface sulfonation and neutralization, amino-terminated block copolymer can be successfully grafted onto graphene surface with the content as high as 81.9 wt%, leading to the macroscopic fluidity of graphene in the absence of solvents at room temperature and the unfolded morphologies in microscopic scale. The excellent solubility of the liquid-like graphene enables the well-dispersion of graphene in a wide spectrum of solvents for a long time. As a lubricant additive in water, the maximum reduction of the friction coefficient and wear rate can reach to 53% and 91% compare with water, which may be due to the formation of tribo-film on the contact interface by electrostatic adsorption and molecular rearrangement of the liquid-like graphene.