The present invention discloses additive for reducing the roasting temperature of fluxed magnetite pellets and a method of using it, consisting of components: B2O3, Mn2O3, the B2O3 and Mn2O3 are pure chemical reagents, the mass of the additive is 0.8%, 4% of the dry basis mass of the magnetite concentrate, respectively, the magnetite concentrate, bentonite clay, calcium flux and additives will be dosed with 12-14% water of the dry base mass ratio of the mixture, prepared into green pellets of 10-12.5 mm in diameter in a disc ball making machine, After the pellets are completely dried, preheat them for 15˜20 min at 600˜1000° C. to ensure that Mn2O3 is fully decomposed, then roasting is carried out for 15 min at 1200° C., and after roasting, the pellets are cooled to room temperature to obtain the finished pellets.