Abstract: Fifteen N1-Substituted fluoroquinolones were optimized by MMPMI. Employing the indexes of molecular connectivity and quantum chemistry. Four equations of QSAR were obtained through stepwise regress. According to the QSAR equations, the antibacterial activities were predicted for four N1-Subsituted fluoroquinolones, which were unreported till now. The four compounds were synthesized and characterized by IR, UV,¹H-NMR and elementary analysis. The determined results show good antibacterial activixinties against G^- and G⁺.