The invention relates to a microporous chitosan oligosaccharide/sodium alginate hemostasis granule and a preparation method thereof. The hemostasis granule comprises a plurality of loose powder granules, wherein a plurality of micropores or gaps are formed among the powder granules. The preparation method comprises the steps that (1) chitosan oligosaccharide, sodium alginate and calcium chloride are taken, crushed and sieved for standby; (2) mixing is performed via a boiling granulator; (3) an adhesive is prepared; a peristaltic pump is connected; the adhesive is sprayed into the granulator; and (4) granulation is observed; sampling and sieving are performed; whether the granulation reaches a standard is observed; the peristaltic pump is stopped after the granulation reaches the standard; hot air drying is performed; shutdown is performed; a material is taken out and sieved; the qualified material is a finished product; and sterilization and packaging are performed. The hemostasis granule has good biocompatibility, can be absorbed by a human body, does not cause toxic or side effects such as allergy and poisoning, and has a good application prospect.