Abstract: Aim ：To study the synthesis and antibacterial activity of new fourth-generation cephalosporin compounds. Methods ：Starting with 7-ACA，the target compounds were obtained by 3-substitution with nitrogen-containing aromatic heterocyclic compounds using TMSI as a catalyst，salt exchange with hydrochloric acid and condensation with 2-(2-substituted aminothiazol-4-yl)-(Z)-2-methoxyiminoacetic acid thiobenzothiazole active esters in the presence of Et₃N.Their antibacterial activity in vitro were evaluated by double broth dilution method. Results and Conclusion ：Nine new compounds were synthesized，and their structures were confirmed by IR，ESI-MS，¹H NMR and elemental analysis.Preliminary results of antibacterial activities in vitro showed that compounds 4c and 4h possessed approximately equivalent antibacterial activity against Gram-positive bacteria in comparison with cefozopran.