Abstract: On the basis of conducting antibacterial experiments on the water extract and ethanol extract of Enteromorpha clathrata, the ethanol extraction process was optimized through single factor experiments and response surface analysis. The main components in the ethanol extract were conventionally qualitatively analyzed, and the antibacterial effects of different solvent extracts were further studied. Finally, the ethyl acetate extract was analyzed using GC-MS. The results showed that the ethanol extract of E. clathrata had better antibacterial effect and better inhibitory effect on Staphylococcus aureus than that of the water extract. The optimal process conditions obtained by response surface analysis were as follows: ethanol volume fraction of 92%, liquid material ratio of 30:1, extraction temperature of 83 ℃, extraction time of 4 h. Under this condition, the diameter of the inhibitory zone of ethanol extract against S. aureus was (1.152±0.015) cm. Conventional qualitative analysis found that the ethanol extract of E. clathrata contains organic acids, sterols, and terpenoids, but did not contain alkaloids, anthraquinone, phenols, saponins, flavonoids and other components. The ethyl acetate extract had the best bacteriostatic effect (the inhibition zone diameter was 2.82 cm), followed by dichloromethane and petroleum ether extracts (the inhibition diameters were 1.68 and 1.06 cm, respectively), and n-butanol and water extracts had no bacteriostatic effect. GC-MS analysis showed that the ethyl acetate extract contained 12 volatile components, mainly acid compounds and aromatic compounds.