OBJECTIVE To study the composition of chemical constituents of Sargassum fusiforme and its in vitro anti- neuroinflammatory activity ，and to provide reference for its development and utilization and the study of pharmacodynamic substances. METHODS UHPLC-QTOF-MS/MS analysis method and GC-MS/MS method were used to analyze the chemical constituents of S. fusiforme . The lipopolysaccharide （1 μg/mL）was adopted to establish the inflammatory model of neuromicroglia BV2. Using paroxetine （5 μg/mL）as positive control ，CCK-8 assay was used to detect the effects of the extracts of S. fusiforme （20，40，60，80，100 μg/mL）on the activity and morphology of neuromicroglia BV 2. The effects of the extracts of S. fusiforme （40，60，80 μg/mL）on the contents of tumor necrosis factor α（TNF-α）and interleukin- 6（IL-6）in cell supernatant were detected by ELISA. RESULTS A total of 103 non-volatile constituents were identified by UHPLC-QTOF-MS/MS ，and 60 volatile constituents were obtained by GC-MS/MS. The extracts of S. fusiforme （40，60，80 μ g/mL） could significantly reduce the abnormally increased activation of neuromicroglia BV 2 and the contents of TNF-α and IL-6 due to lipopolysaccharide （P＜0.05 or P＜0.01）. CONCLUSIONS The study establish the full spectrum of chemical constituents of S. fusiforme ，and it is confirmed that fusiforme has certain in vitro anti-neuroinflammatory activity.