The invention provides N,N,N,N-tetramethylethylenediamine sulphonate ionic liquid and a preparation method thereof, belonging to the technical field of organic chemical synthesis. The preparation method of the ionic liquid comprises the following steps: using N,N,N,N-tetramethylethylenediamine and sultone to react at room temperature in the presence of acetone and absolute ethanol to obtain N,N,N,N-tetramethylethylenediamine sulphonate inner salt, and then using N,N,N,N-tetramethylethylenediamine sulphonate inner salt to react with inorganic acid or organic acid to obtain disulfonic acid groupacidic ionic liquid with N,N,N,N-tetramethylethylenediamine cationic group. The prepared ionic liquid can be used as the catalyst or solvent of organic reactions, in particular to the catalytic reaction of inorganic acid or organic acid; compared with the existing monosulfonic group acidic ionic liquid used as catalyst, the N,N,N,N-tetramethylethylenediamine sulphonate ionic liquid has higher catalytic activity, less dosage, less loss in cycle use, higher product yield and more environmentally friendly.