Weih 4yearold ‘Mengyuan’ Cerasus humilis was used as the test material, this experiment conducted to explore the phenolic contents (total phenol, total flavonoids, proanthocyanidins, anthocyanin and flavonol) and antioxidant activities (total antioxidant, iron ion reduce power, DPPH·clearance rate and ·OHclearance rate) of leaves in different growing stages of C. humilis, so as to provide theoretical basis for the further development and application of C. humilis leaves resources. The results show that: (1) the contents of phenolic substances in leaves of C. humilis increased firstly and then decreased, and reached the maximum at the pigmentation expansion stage. (2) The antioxidant activities of phenolic compounds were similar to that of phenolic compounds, and reached the maximum at the pigmentation expansion stage, except for individual differences. (3) During the pigmentation expansion stage, the contents of phenolic substances and their antioxidant activities in leaves of C. humilis were the highest, followed by total flavonoids and procyanidins, and flavonols and anthocyanins. In conclusion, the contents of phenolic compounds in leaves of C. humilis had obvious synergistic change relationship with its antioxidant activity, and the antioxidant activity increased or decreased with the increase or decrease of the contents of phenolic compounds. Apart from proanthocyanidin and anthocyanins, the accumulation peak of phenolic substances and total antioxidant capacity of C. humilis leaves reached the highest in the pigmentation expansion stage.