Objective To establish a new flow-injection chemiluminescence(CL) method for the determination of hydrocortisone.Methods In H2SO4 solution,hydrocortisone could obviously enhance the chemiluminescence intensity of the reaction of KMnO4-Na2SO3 system.Based on this,a new flow-injection CL method for the determination of hydrocortisone was developed.Results There was a good linear relationship between CL intensity and the concentration of hydrocortisone in the range of 1.0?10-9-1.0?10-6g/mL.The detection limit was 4.0?10-10g/mL at a signal-to-noise ratio of 3∶1.The RSD of 11 assays was 2.2%.Conclusion This method can be successfully used to determine the quantity of hydrocortisone in injection.It is rapid,accurate,simple,and has high sensitivity and wide linear range.