The invention discloses a preparation method for 1,2,4,5-tetra-substituted imidazole derivatives and a catalyst for preparation, and belongs to the technical field of ionic liquid catalysis. In a preparation reaction, the molar ratio of benzil to aromatic aldehyde to aromatic amine to ammonium acetate is 1 to 1 to 1 to (1-1.2), the molar amount of the ionic liquid catalyst is 7-12% of the used benzil molar amount, the volume amount of a reaction solvent ethanol aqueous solution in milliliter is 6-8 times of the molar amount of the benzil in millimole; the reflux reaction time is 15-45 min, cooling is performed to room temperature after the reaction is finished, suction filtration is performed, the filter residue is washed with the ethanol aqueous solution and subjected to vacuum drying to obtain the 1,2,4,5-tetra-substituted imidazole derivatives. The preparation method has the advantages of high catalyst activity, biodegradability, simple product purification, high raw material utilization rate, simple and convenient operation in the whole preparation process and the like, and is convenient for large-scale industrialized application.