Chive (Allium schoenoprasum L.) has a strong antioxidant property as it contains abundant phenolic compounds and ascorbic acid (AsA). In the present study, we investigated the metabolism of phenolic compounds and the change in antioxidant activity in different tissue parts of post-harvest chive. The results showed that compared with the bottom white part (BW), the round green part (RG) exhibited significantly higher content of phenolic compounds, increased enzyme activities and antioxidant activities, indicating that phenolic compounds were mainly synthesized in RG. The expression levels of genes (phenylalanine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H) and 4-coumaroyl-CoA ligase (4CL)) and their corresponding enzymes activities rapidly decreased in RG, whereas they were maintained in BW, suggesting that senescence occurred more rapidly in RG compared with that in BW. Our study provides a theoretical foundation for further research and development of different parts of Allium plants and offers a basis for consumers' nutritional considerations.