The invention discloses high-performance 
internal combustion engine oil capable of performing 
viscosity classification and a preparation method thereof. The 
internal combustion engine oil comprises synthesized 
base oil, high-temperature 
antioxidant, 
metal clearing agent, ash-free dispersing agent, anti-oxidation preservatives, nano multi-effect abradant, 
viscosity index improver, 
pour point depressant and oiliness agent. The high-performance 
internal combustion engine oil has the advantages that the internal 
combustion engine oil is outstanding in 
energy conservation and environment protection performance, excellent in 
wear resistance and friction resistance, good in fuel economy, excellent in low-temperature flowability, outstanding in high-temperature 
oxidation resistance and high in abrasion resistance; the influence of temperature on the 
viscosity change of the internal 
combustion engine oil is small, the internal 
combustion engine 
oil can flow under a low-temperature condition and keep proper viscosity in a high-temperature environment, and the internal combustion engine 
oil can reduce 
engine wear and prolong the service life of an engine; in addition, the internal combustion engine oil prepared by the method is high in extraction purity and cannot be easily oxidized and degraded into 
oil sludge and 
carbon deposition, and accordingly the oil change period of the internal combustion engine oil is long.