Multiple spectroscopic, chromatographic, and chemical reaction methods were combined to investigate the chemical components in the fruits of Elaeagnus angustifolia L. As results, thirty-two compounds were obtained from it as natural products. Six of them, elangphenosides A (1), B (2), C (3) and D (4), elangmegastigmanoside A (5), and elangorganic acid A1 (6) were retrieved by Scifinder as previously undescribed ones. Additionally, a previously undescribed artificial product, elangorganic acid A2, as well as a known artificial one, (3R) 5-ethoxy-3-(ethoxycarbonyl)-3-hydroxy-5-oxopentanoic acid, were yielded. Following the phytochemical investigation, LC-MS analysis was employed to conduct a systematical characterization of the constituents from E. angustifolia fruits. Ultimately, fifty-six compounds, including seventeen phenols, one ionone, twenty-four triterpenes, and fourteen other ones, were unambiguously detected and identified. Moreover, in vitro anti-inflammatory activity screening of forty-four natural compounds presented in E. angustifolia fruits was performed by using the LPS-induced RAW264.7 cell model. Twenty-six compounds, including phenols, organic acids, and other compounds, showed assignable activity. Furthermore, their structure-activity relationships were summarized. Combined with the previous research work in our lab, triterpenes, phenols, and organic acids were speculated to be key components during the E. angustifolia fruits exerting anti-inflammatory activity. In summary, this article fully explored the chemical composition of E. angustifolia fruits, assayed their in vitro NO production inhibitory effects, greatly expanding its material foundation and laying a solid foundation for further research and development.