Lycium barbarum L. bud tea and leaf tea are functional processed products made from L. barbarum buds and leaves with traditional green tea processing techniques. Based on an extensive targeted metabolomics technology, this study systematically analyzed the chemical composition of L. barbarum bud tea and leaf tea, identified their differential compounds, and explored the effects of water-extracted substances on the activities of pancreatic lipase and α-Amylase. The results showed that the contents of total phenols, total flavonoids, and chlorogenic acid in the bud tea were 36.09 ± 1.97 mg/g, 7.44 ± 0.31 mg/g, and 4.18 ± 0.10 mg/g, respectively, 66.25%, 34.78%, and 22.58% higher than those in the leaf tea, respectively. A total of 594 metabolites were identified through the metabolomics analysis, mainly including flavonoids, phenolic acid compounds, alkaloids, amino acids and their derivatives, organic acids, lignans and coumarins, terpenoids, ands steroid compounds. Among them, flavonoids, phenolic acids, alkaloids, and amino acids and their derivatives accounted for approximately 58%. Compared with the leaf tea, the bud tea was significantly enriched with flavonoids, phenolic acid compounds, nucleotide compounds, lignans, and coumarins. Delphinidin 3-O-galactoside, cyanidin-3-glucoside, and cyanidin-3-O-glucoside were identified as significantly differential metabolites. Both L. barbarum bud tea and leaf tea exhibited good inhibitory effects on pancreatic lipase and α-Amylase, with the highest inhibition rates being 68.71%, 77.33%, 76.08%, and 69.96%, respectively. The contents of anthocyanins and their derivatives, including delphinidin-3-O-galactoside, cyanidin-3-glucoside, cyanidin-3-O-glucoside, cyanidin-O-hexoside, delphinidin-O-hexoside, and delphinidin diglucoside, were positively correlated with the activities of the two enzymes. These results underpin functional exploration and quality standardization of L. barbarum bud/leaf tea products.