In order to investigate the influence of microstructure of Dagushan magnetite flavor powder on its oxidation roasting properties, SEM-EDS is used to analyze the presence modes of SiO₂ in two high-silica magnetite powders from Dagushan Pellet Plant, and TG/DTA is used to analyze the oxidation properties of high-silica magnetite powders, and briquetting and roasting of high-silica magnetite is used to analyze the continuous crystal growth characteristics of high-silica magnetite powders. The XRD-Rietveld refinement results show that the main phase of 1# magnetite is Fe₃O₄, which contains part of Fe₂O₃ and SiO₂; the main phase of 2^# magnetite is Fe₃O₄ and SiO₂. SEM analysis results show that SiO₂ in both high-silica magnetites is mainly in the form of quartz tightly bound to Fe₃O₄ magnetite. TG/DTA differential thermal analysis finds that: the initial oxidation temperature of 1^# magnetite is 270 ℃, and the comprehensive oxidation index is 2.442 2. There are more primary hematite in 1# magnetite, the temperature required for oxidation of primary hematite is higher and the oxidation is relatively poor; the initial oxidation temperature of 2# magnetite is 237 ℃, and its comprehensive oxidation index is 9.046 2. So the oxidation roasting property of 2^# magnetite is better. By adjusting the ratio of 1# and 2^# magnetite, the initial oxidation temperature increases with the increase of 1^# magnetite ratio, and the comprehensive oxidizability index decreases from 5.160 9 to 3.671 9. The compressive strength test of single magnetite briquettes after oxidation and roasting shows that: the compressive strength of 2^# magnetite briquette is 2300 N/P, and the compressive strength of 1^# magnetite briquette is 2100 N/P. The compressive strength of 2^# magnetite briquette is better than the one of 1^# magnetite. SEM analysis founds that the newly-born hematite in 1^# magnetite is mostly dot-like contiguous crystals with many micropores, and the consolidation effect is poor. The newly-born hematite in 2^# magnetite mostly presents lamellar contiguous crystals, so its consolidation effect is better. Therefore, when preparing pellets by adding 1^# high-silica magnetite, the preheating roasting temperature should be increased appropriately to make the magnetite fully oxidized and ensure the growth of newborn hematite continuous crystals.