The invention relates to the field of daily chemicals and the industry of medicines, and particularly relates to iodomethyltriazole starch containing a nicotinamide group, and a preparing method and applications thereof. The structure formula of the iodomethyltriazole starch containing the nicotinamide group is shown as a formula (1), wherein the average degree of polymerization n is 5-12000. The method is efficient in reaction and prone to popularization. Needed devices and raw materials are easily available. Research proves that the synthesized iodomethyltriazole starch containing the nicotinamide group has good water solubility and extremely good fungistatic activity, enhances bioactivity of the starch, expands the application range of starch and can be widely used in the fields of daily chemicals and medicines.