Abstract: AimTo explore new agents of quinolone derivatives with high activity against Gram-positive organisms. Methodsdl-7-(4,4-Dimethyl-3- aminomethylpyrrolidinyl)-quinolones were designed and synthesized, and their activity against Gram-positive organisms was tested in vitro. ResultsTen target compounds were obtained. The structures of these compounds were confirmed by ¹H NMR, MS. The target compounds with dl-4,4-dimethyl-3-(methyl) aminomethylpyrrolidine side chains had high activity against Gram-positive organisms. Especially the MIC values of compound 22 for 4 strains of Gram-positive resistant bacteria (two strains of MRSA and two of MRSE) were 0.015-0.5 mg·L^-1, which exhibited more potent activities than gatifloxacin (4-128 times). Its MIC value for Pseudomonas aeruginosa 03-5 (0.008 mg·L^-1) was 4 times as that of gatifloxacin (0.03 mg·L^-1). ConclusionThe compound 22 showed high activity against Gram-positive organisms in vitro and it is worth of more investigation.