Golden buckwheat, also called Fagopyrum dibotrys (D. Don) H. Hara, is a plant of the genus Buckwheat in the buckwheat family. The aim of this study was to screen the bioactive ingredients of golden buckwheat extract and investigate the protective effect on acute lung injury (ALI). The ethyl acetate extract (EAE) was identified as the active fraction in LPS-induced RAW264.7 cells, with gallic acid, proanthocyanidin B2, and epicatechin at 0.0563%, 0.3707%, and 0.3868%, respectively. At the same time, 20 compounds (mainly flavonoids and organic acids) were identified by UPLC-Q-Exactive Orbitrap-HRMS in EAE. Furthermore, the EAE reduced lung histopathology scores in mice with ALI, decreased the dry-to-wet weight ratio of lung tissue, and significantly inhibited the concentrations of IL-1β, TNFα, and IL-6 in bronchoalveolar lavage fluid (BALF). It also reduced the number of leukocytes, decreased the activity of MPO in lung tissue, and inhibited the levels of TLR4/NLRP3 pathway mRNA and protein in lung tissue. Our study indicated that golden buckwheat as a source of functional food prevents or treats associated lung diseases by modulating the activation of the TLR4/NLRP3 signaling pathway.