Abstract: A new rapid determination method of ascorbic acid content in vegetable by potassium permanganate titrimetry was studied. Based on KMnO4 quantitatively oxidating ascorbic acid to dehydro-ascorbic acid at room temperature,after masking interfering ions,the metaphosphori extraction solution of sample can be titrated with KMnO4 standard solution directly to determine ascorbic acid content according to color change. The method was applied for the determination of ascorbic acid in vegetable with the relative standard deviation of less than 1.0% and the recoveries of standard addition of 93.8%～101.2%. It has the characteristics of easy operation,fast determination and little disturbance. The determination results are consistent with those by China national standard method with both relative deviations of less than 2.5%.

Key words: potassium permanganate method, vegetable, ascorbic acid