There is provided an aqueous liquid pharmaceutical composition which comprises Gatifloxacin (chemical nomenclature: (±)-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-7-(3-methyl-1-piperazinyl)-4-oxo-3-quinoline carboxylic acid) or its salt and disodium edetate. Further, there are provided a method for raising corneal permeability of Gatifloxacin, a method for preventing precipitation of Gatifloxacin crystals, and a method for preventing coloration of Gatifloxacin by incorporating disodium edetate into an aqueous liquid preparation containing Gatifloxacin or its salt.