The invention discloses spirocyclo-quaternary ammonium salt for a supercapacitor and a preparation method of the spirocyclo-quaternary ammonium salt. The spirocyclo-quaternary ammonium salt for the supercapacitor is characterized in that the formula is represented as following, wherein in (A), n, m= 1, 2, 3; in (B) or (C), n, m= 1, 2, 3; and p=1, 2. The preparation method includes that water is used as a reaction medium, cyclic amine and dihalogenation amine or glycol di-sulphonate ester are subjected to condensation reaction under the action of alkali, and obtained spirocyclo-quaternary ammonium salt and lithium bis(oxalato)borate are subjected to ion exchanging and then to purification to obtain the target spirocyclo-quaternary ammonium salt. According to the spirocyclo-quaternary ammonium salt for the supercapacitor and the preparation method of the spirocyclo-quaternary ammonium salt, raw materials are easily obtained, reaction selectivity is good, qualities of the spirocyclo-quaternary ammonium salt are high, and the method is suitable for large scale production, and the supercapacitor which is composed of the spirocyclo-quaternary ammonium salt is low in internal resistance, high in electrostatic capacity and excellent in cycling performances.