Provided is a Lactiplantibacillus plantarum TCI837, deposited in the Leibniz Institute DSMZ under an accession number of DSM 33843. Based on this, the Lactiplantibacillis plantarum TCI837 can be used to prepare a composition for supplementing iron and/or promoting the absorption of iron in a subject, and to prepare a composition for improving the gut microbiota in a subject. In addition, the composition may be an iron supplement composition containing the Lactiplantibacillus plantarum TCI837 and an iron supplement.