The invention provides a multi-graded anti-wearing hydraulic oil composition and a preparation method thereof. The multi-graded anti-wearing hydraulic oil composition is prepared from the following components according to the total weight of 100%: (a) 85%-95%, preferably 88%-93%, of type III hydroisomerizing
base oil; (b) 3%-5%, preferably 3%-4.5%, of a
viscosity index improver; (c) 0.5%-4%, preferably 1.5%-3%, of an
antioxidant; (d) 0.5%-5%, preferably 0.5%-2%, of an extremely pressure anti-wearing agent; (e) 0.002%-0.020%, preferably 0.005%-0.015%, of an anti-
foaming agent; and (f) 0.5%-4%, preferably 1%-3%, of a cleaning dispersant. The product provided by the invention has relatively high comprehensive performance and low cost and has good
viscosity-temperature characteristics, low-temperature flowability and oxidization stability; meanwhile, nano
titanium dioxide which has dual advantages of fluid
smoothing and
solid smoothing is compounded with dialkyldithiophosphate, so that the product has good bearing capability and anti-wearing performance; and furthermore, when the product is used, the number of times of replacing
oil can be reduced, so that the working efficiency of
hydraulic machinery is improved and the aims of energy saving and environmental friendliness are realized.