The invention provides a preparation method of a chitosan-based drug-loading composite antibacterial superfine fiber membrane. The preparation method comprises the following steps: S1, adding antibacterial medicine powder into an acetic acid aqueous liquid with mass fraction of 2-90%, stirring by a magnetic stirrer to fully dissolve, weighing chitosan and polyoxyethylene powder into the liquid, and stirring to obtain a spinning liquid; and S2, adding the spinning liquid into an unfolder for electrostatic spinning, putting the obtained electrostatic spinning membrane in a drier holding a 25% glutaraldehyde aqueous liquid for crosslinking for 12-36 hours, drying, and finally obtaining the chitosan-based drug-loading composite antibacterial superfine fiber membrane, wherein the diameter of the fiber is 150-600nm. The electrostatic spinning superfine fiber prepared by the invention has the characteristics of good adhesion, flexibility, good antibacterial performance, hemostasis, percolate absorption, healing and the like. By designing the compounding proportion of chitosan and antibacterial drug, the membrane can satisfy different anti-infection demands, wound nursing of different types and surgical dressing field.