In order to further investigate the synergistic effect of ZrO₂ nanoparticles and low-salinity water，the low-salinity water was obtained by diluting the formation water of Taha oilfield by 11—200 times. Meanwhile，in order to improve the dispersion of ZrO₂ nanoparticles in low-salinity water， ZrO₂ nanoparticles with 50—100 nm were modified by the coupling agent 3-aminopropyltrimethoxysilane. The structure and morphology of the particles were characterized by infrared spectroscopy，transmission electron microscopy and thermogravimetric analyzer. The dispersion stability， interfacial properties and oil displacement effect of nanofluids combined with low-salinity water and modified ZrO₂ nanoparticles were evaluated. The results showed that compared to formation water，the greatest increase in recovery（5 percentage points）was achieved by injecting 1.5 PV low-salinity water diluted 110 times. The particle size of the modified ZrO₂ nanoparticle was about 30 nm. Compared to unmodified nanofluid prepared by formation water，the index of stability of the modified nanofluid prepared by low-salinity water decreased from 22.9 to 7.6，the interfacial tension was further reduced by 2 mN/m，the wettability of rock surface was further shifted to water-wetness，and then the lowest value of work of adhesion decreased from 27.72 J/cm¹ to 8.65 J/cm¹. The increase in temperature had a positive effect on the reduction of oil-water interfacial tension，contact angle and work of adhesion. When the dosage of modified ZrO₂ nanoparticle increased from 0.005% to 0.050%，the recovery rate of nanofluid increased first and then decreased. The optimum dosage of nanoparticle was 0.020% ，with a recovery rate increment of 12.6 percent points. The synergistic oil enhancement effect of low-salinity water and modified ZrO₂ nanoparticles was remarkable，which had good application prospects.