【Objective】 This research aims to reveal the chemical components of the leaves of Dendrocalamus brandisii and accurately identify the application value of these leaves, hoping to provide a scientific basis for the development and utilization of this species. 【Method】 The research employed a Waters ACQUITY UPLC HSS T3 C18 (2.1 mm × 100 mm, 1.8 μm) liquid chromatography column. Elution was conducted at a flow rate of 0.35 mL/min using a 0.04% (volume fraction, same as below)aqueous acetic acid solution as phase A and a 0.04% acetic acid acetonitrile solution as phase B. The electrospray ion source was selected in a triple quadrupole, where detection was scanned under optimized declustering voltage and collision energy. The self-built database of Wuhan Metware Biotechnology Co., Ltd. was used to qualitatively identify substances based on secondary spectrum information. Metabolites were quantified using a triple quadrupole mass spectrometer (MRM), with the relative content of each substance determined by integrating and correcting compound characteristic ion chromatographic peak areas. 【Result】 The 407 metabolites were detected in ten categories, including 79 flavonoids, accounting for 19.41% of the total compounds. There were 61 types of lipids and 55 phenolic acids, accounting for 14.99% and 13.51% of the total detected compounds, respectively. There were 55 types of amino acids and their derivatives and 35 organic acids, accounting for 13.51% and 8.60% of the total detected compounds, respectively. Thirty-one nucleotides and their derivatives accounted for 7.62% of the total detected compounds, and 28 alkaloids accounted for 6.88% of the total detected compounds. There were 17 lignans and coumarins, accounting for 4.18% of the total detected compounds. One terpene accounted for 0.24% of the total detected compounds. There were 45 other compounds, accounting for 11.06% of the total detected compounds. 【Conclusion】 Besides basic nutritional components, these leaves contain many medicinal compounds. Flavonoid compounds, in particular, serve as one of the primary active ingredients in these leaves. These compounds have significant development and application prospects in human health and animal care. This study provides a scientific basis for further development and utilization of medicinally active substances present in the leaves of Dendrocalamus brandisii.