A series of 4-hydroxycoumarin derivatives were designed and synthesized in order to find some more potent antibacterial drugs. Their antibacterial activities against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus were tested. These compounds showed good antibacterial activities against Gram-positive strains. Compound 4 g represented the most potent antibacterial activity against Bacillus subtilis and S. aureus with MIC of 0.236, 0.355 μg/mL, respectively. What's more, it showed the most potent activity against SaFabI with IC50 of 0.57 μM. Molecular docking of 4 g into S. aureus Enoyl-ACP-reductase active site were performed to determine the probable binding mode, while the QSAR model was built to check the previous work as well as to introduce new directions.