The invention discloses a method of using dopamine for rapidly crosslinking chitosan to prepare hemostatic sponge, and belongs to the field of biomedical materials. The dopamine is adopted to react with amidogen on a chitosan chain, and meanwhile a self-polymeric reaction is performed, so that chitosan chain sections are crosslinked to form a cross-linked network structure, and the obtained chitosan sponge has the certain mechanical strength. In the reaction process, the oxidizing agent sodium periodate is added to accelerate the reaction, and therefore the time spent for preparing the chitosan hemostatic sponge can be greatly shortened. The chitosan hemostatic sponge has the good biocompatibility, also has the strong water expansion performance, mechanical performance, water retention and moistening performance and biodegradability, has the good analgesic and hemostatic effects, prevents wound contamination and infection, promotes healing of injured tissue, and can be possibly applied to clinical first aid and hemostasis.