A method was developed for the fast determination of pyrrolidinium ionic liquid cations by ion-pair chromatography with indirect ultraviolet detection on a monolithic column.The analytes were separated using a mobile phase of background ultraviolet absorbing reagent-ion-pair reagent-organic solvent on a reversed-phase silica-based monolithic column.The effects of the background ultraviolet absorption reagents,detection wavelength,ion-pair reagents,organic solvents,column temperature and flow rate on the separation and determination of pyrrolidinium cations were investigated.The optimized chromatographic conditions for the determination of the cations were as follows: using 80%(0.5 mmol/L 4-amiophenol hydrochloride-0.1 mmol/L 1-heptanesulfonic acid sodium) aqueous solution-20%(V/V)methanol as mobile phase,detection wavelength 230 nm,column temperature 30 ℃,flow rate 2.0 mL/min.Under the optimal conditions,N-methyl,ethyl-pyrrolidinium cation,N-methyl,propyl-pyrrolidinium cation and N-methyl,butyl-pyrrolidinium cation were successfully separated within 1.6 min.The detection limits(S/N=3) were 0.02,0.03 and 0.07 mg/L,respectively.Relative standard deviations(n=5) were no more than 0.4%.The method has been applied to the analysis of the ionic liquids synthesized by chemistry laboratory,with spiked recoveries of 97.4%-98.0%.The method is rapid,simple,accurate,reliable and practical.