Analyte pulse perturbation (APP) technique was applied to the study of the perturbation of ascorbic acid (AA) on the lactic acid-acetone-BrO - 3-Mn 2+-H 2SO 4 oscillating reaction, and AA was determined using this new oscillating chemical system. Influence of experimental variables was investigated. The linear range lies between 5.0×10 -7- 5.5×10 -5 mol/L, and the precision and throughput were quite good ( 2.43% as RSD, and 8-10 samples/h, respectively). This method was applied to the determination of real samples and the results were satisfactory. Some aspects of the potential mechanism of action of AA on the oscillating systems are discussed. Analyte pulse perturbation (APP) technique was applied to the study of the perturbation of ascorbic acid (AA) on the lactic acid-acetone-BrO - 3-Mn 2 + -H 2 SO 4 oscillating reaction, and AA was determined using this new oscillating The linear range lies between 5.0 × 10 -7 and 5.5 × 10 -5 mol / L, and the precision and throughput were quite good (2.43% as RSD, and 8-10 samples / h, respectively). This method was applied to the determination of real samples and the results were satisfactory. Some aspects of the potential mechanism of action of AA on the oscillating systems are discussed.