Abstract: Objective: To establish a method for determining the total flavonoid content and antioxidant activity of Sapium discolor, correlation analysis was conducted based on yield, and the analytic hierarchy process (AHP) was employed to evaluate the different varieties of Sapium discolor. Methods: The total flavonoid content in Sapium discolor cultivars during summer and autumn was analyzed, alongside six phenotypic characteristics such as plant height and yield. The ABTS and DPPH methods were used to determine the antioxidant activity of different batches of Sapium discolor extracts. The varieties with the best comprehensive traits were selected using the analytic hierarchy process. Results: (1) ‘Qingwu 2’ exhibited higher yield and better phenotypic traits compared to other varieties at two harvesting periods. (2) From the perspective of total flavonoid content and antioxidant activity, Sapium discolor leaves harvested in August had higher total flavonoid content and better antioxidant activity. The older leaves contained higher total flavonoid content and showed better antioxidant activity compared to the new leaves. ‘Qingwu 2’ had higher total flavonol content than other varieties, while ‘Longwu 3’ and ‘Qingwu 4’ showed higher antioxidant activity. (3) Correlation analysis and AHP-based scores revealed that total flavonol content was positively correlated with yield and antioxidant activity. The AHP results indicated that ‘Qingwu 2’ had the highest comprehensive score. Conclusion: The leaves harvested in summer have higher yields and better medicinal quality, with older leaves showing superior medicinal properties compared to new leaves. There is a significant positive correlation between total flavonoid content, yield, and antioxidant activity. ‘Qingwu 2’ possesses the best comprehensive traits and is suitable for the breeding of new varieties.