Abstract: Nanomaterials have been more and more used in drilling fluids, gaining good results in drilling operation. It has been found in the field application that the nanomaterials always become aggregated as the concentrations increase, making it difficult for the nanomaterials to take effect. Based on the study of the mechanisms of nanomaterial aggregation, a nanomaterial was grafted to render it good dispersity in drilling fluid. The molecules of the nanomaterial have good flexibility and deformability. The molecules of the nanomaterial can be adsorbed on the surface of rocks, thereby enhancing the ability of the nanomaterial to plug micro fractures and fissures. A nanomaterial filter loss reducer has been synthesized to formulate a drilling fluid with other nanomaterial additives, such as lubricant and shale inhibitor. The nanomaterial drilling fluid functions properly at 150℃, and has properties as follows:API filter loss ≤ 2.4 mL, HTHP filter loss ≤ 9.8 mL, coefficient of friction ≤ 0.04, percent recovery of permeability of cores ≥ 91%, and percent recovery of drilled cuttings in hot rolling test ≥ 90.5%. Field application has shown that the nanomaterial drilling fluid had good lubricity and reservoirs drilled were effectively protected from being damaged.