<p>Improving the stability and anti-wear and friction reduction properties of lubricants used in water pump thrust bearings is economically important. Addition of modified zirconia (ZrO₂) nanoparticles to the lubricant is an effective method. ZrO₂ / lubricating oil nanofluids modified by silane coupling agent γ-methacryloxypropyltrimethoxysilane (KH570) were prepared by surface modification technology. Firstly, the surface properties of modified particles were studied. The results showed that the highest grafting rate of KH570 was found in the modified nanoparticles with 20&#xa0;mL KH570, and the grafting rate was 4.818%. At the same time, it was found that the modified nano-zirconia changed from hydrophilicity to hydrophobicity, and the lipophilicity and dispersion stability were also improved. Finally, the stability and friction and wear properties of the prepared nanofluids were investigated. In stability experiments, the nanofluids prepared from KH570-modified nanoparticles showed more excellent stability compared to the addition of sodium dodecylbenzene sulfonate (SDBS), and the former nanofluids had completely precipitated after 35&#xa0;days. The modified nano-ZrO₂ has better tribological properties than the unmodified ZrO₂. The optimal coefficient of friction of the modified nano ZrO₂ lubricant is 0.0753, which is 40.71% lower than that of the L-TSA46 base oil, and the diameter of the abrasion marks has been reduced by up to 28.1%. This study provides a practical solution to the key problem in industrial lubrication (balance between stability and friction performance), which has important engineering significance and market prospects.</p>