Regulating the wettability contact angle of oil-water interface by adding nanoparticles is a hot topic in the field of enhanced oil recovery technology. However, the lack of microscopic experimental data makes the mechanism of nanofluid displacement always controversial. The microscopic dynamic contact lines of nanofluids formed by the addition of nanoparticles to droplets were measured for the first time using the tapping mode imaging principle of atomic force microscopy. The results show that the microscopic contact angles of the silicone oil droplets and n-propanol droplets are reduced by 1.6° and 0.9°, respectively, and the contact lines produces a convex bending within a thickness of 20 nm, that is consistent with the addition of nano-quartz particle size. The generation of convex nanobending structures provides direct experimental evidence for the structure disjoining pressure theory that particles enhance the wettability of the system.