The increasing demand for hydrocarbons has led to a hope of developing more efficient recovery techniques such as nanotechnology and low-salinity water (LSW). In this study, interfacial tension (IFT) reduction was proposed as an important enhanced oil recovery mechanism of nanofluid injection, so IFT measurement between crude oil and nanofluid was performed by using pendant drop method. Introducing silica hydrophilic nanoparticles into the brine-oil system was observed to generate lower IFT and had the potential to produce more oil. Therefore, for LSW injection method, the effects of three different ions and total dissolved solid are investigated. In order to investigate the recovery mechanisms of nanofluids, IFT and contact angle have been measured. The experimental results indicate that the nanofluids can reduce the IFT and make the rock surface more water wet.