The inhibiting effect of ciprofloxacin, norfloxacin and ofloxacin on the corrosion of mild steel in 1 mol.L-1 HCl and the mechanism were studied at different temperatures using mass loss measurement, electrochemical method, and X-ray photoelectron spectroscopy (XPS). Effective inhibition was shown by mass loss, potentiodynamic polarization and impedance spectroscopy measurement. The corrosion rate of the metal in the mass loss measurement, and the corrosion reaction on cathode and anode in the electrochemical measurement were accelerated when temperature was increased. XPS results showed that the inhibitors adsorbed effectively on the metal surface.