NOVELTY - Method of producing antibacterial medicine involves (a) adding starch into water and heating to obtain sticky starch solution; (b) adding gelatin to the starch solution and dissolving to obtain gelatin/starch solution; (c) dissolving chitosan in the gelatin/starch solution and stirring to obtain chitosan/gelatin/starch solution; (d) mixing antibacterial medicine with chitosan/gelatin/starch solution and heating mixture; (e) cooling the mixed solution and processing into grain shaped pill; and (f) drying product.    USE - The method is useful for producing antibacterial medicine used for fisheries (claimed).    ADVANTAGE - The medicine has uniform internal porosity structure, large porosity, uniformly distributed apertures, and good connectivity between apertures, and hence is uniformly distributed in the carrier, and has obviously improved stability in seawater and is not easily dispersed. The medicine is prepared using natural gelatin, chitosan and starch molecules which are friendly to environment.    DETAILED DESCRIPTION - Method of producing antibacterial medicine involves (a) adding starch into water of 70-90 degrees C and heating to obtain 10-20 %mass sticky starch solution; (b) adding gelatin to starch solution and dissolving at 70-90 degrees C to obtain 1-10 %mass gelatin/starch solution; (c) dissolving chitosan in the gelatin/starch solution, and maintaining temperature at 60 degrees C and stirring to obtain 5-20 %mass chitosan/gelatin/starch solution, where mass ratio of starch, chitosan and gelatin is 4:3:1; (d) mixing antibacterial medicine with the chitosan/gelatin/starch solution and heating at 40-60 degrees C and dispersing to obtain 50 %mass viscous antibacterial medicine containing chitosan/gelatin/starch solution; (e) cooling the chitosan/gelatin/starch solution to room temperature, removing air using water pump by mixing the cooled solution repeatedly and processing into grain shaped pill; and (f) drying the obtained pill in vacuum at room temperature for 24 hours, where the pill comprises 1-50 %mass antibacterial medicine.