The invention belongs to the field of 
chemical engineering, and relates to an environment-friendly, energy-saving, totally-synthesized, and wear-resistant hydraulic oil and a preparation method thereof. The hydraulic oil comprises the following components: 
base oil, an extreme pressure anti-wear additive, an 
antioxidant, an antirust component, a 
viscosity index improver, and an antifoaming agent, wherein the 
base oil is a mixture of 3-ethyl-1-hexyl 
imidazole trifluorosulfonate and alkenes, and the extreme pressure anti-wear additive is 
zinc dialkyl dithiophosphate. The preparation comprises two parts: preparing 3-ethyl-1-hexyl 
imidazole trifluorosulfonate and mixing raw materials. The synthesized 
ionic liquid has the advantages of excellent 
thermal oxidation stability, high 
viscosity index, good dissolving performance on 
inorganic salts and organic matters, and good anti-wear and 
friction reducing effect; and the 
ionic liquid is taken as the basic liquid to prepare the environment-friendly, energy-saving, and wear-resistant hydraulic oil. The preparation method greatly promotes the development of anti-ware hydraulic oil to directions of environmental compatibility, biodegradability, and renewability, and the 
ionic liquid may be applied to the practical application of liquid oil.