The invention discloses a preparation method of a high-wax crude oil pour point depressant containing ionic liquid. The preparation method specifically comprises the following steps: step 1, adding octadecyl acrylate, styrene, maleic anhydride and ethyl ionic liquid into a reactor with an electromagnetic stirrer, a refluxing condenser and a nitrogen gas leading-in pipe; step 2, adding N,N-dimethylformamide into the reactor as a solvent; step 3, raising temperature to reaction temperature of 70 DEG C to 85 DEG C; step 4, precipitating; step 5, carrying out vacuum drying; step 6, crushing by a crusher and sieving a product with the granularity of 80 meshes, so as to obtain a finished product. The preparation method of the high-wax crude oil pour point depressant containing the ionic liquid has the beneficial effects that a non-polar part and wax are commonly polymerized, and crystal forms of wax crystals are twisted due to polar linking, so that the wax crystals cannot continuously grow to form a network structure; meanwhile, the ionic liquid gives charges to molecules of the pour point depressant, so that a condition that the wax crystals are connected with each other to form a three-dimensional net-shaped structure is prevented.