The invention discloses biomedical polysaccharide hemostatic and healing sponge and a preparation method thereof, and belongs to the technical field of medical materials. The preparation method comprises the following steps: firstly, dissolving a polysaccharide material carboxymethyl cellulose, hyaluronic acid or a mixture thereof into an alkaline solution, stirring sufficiently, and swelling into colloid; secondly, adding a crosslinking agent into the colloid, stirring sufficiently, incubating into uniform gel, and dialyzing and purifying the obtained gel; thirdly, adding glycerin into the purified product, stirring at a high speed for bubbling, and pouring into a lyophilizing disk; and finally, performing freeze drying at a low temperature to obtain dehydrated sponge. The hemostatic and healing sponge prepared with the method is good in flexibility, do not drop crumbs, is strong in liquid absorption, can provide a wet environment to a wound, is non-stick to the wound, is good in biocompatibility, is qualified in heavy metal detection and endotoxin detection, is non-cytotoxic in a bio-safety test, is free of intradermal irritation and sensitization response, and has the functions of stopping bleeding rapidly, absorbing exudate and promoting wound healing.