Abstract: In order to effectively provide guide for beneficiation tests on an iron ore in Gansu，process mineralogy of the sample was studied.The results showed that:①iron ore with iron grade of 37.89% is semi self-fluxing low sulfur magnetite ore.The useful mineral is magnetite，among which magnetic iron account for 79.31% of total iron.②The ore is mostly constructed by block structures，then disseminated and banded structures.The main structure forms of the ore are xenomorphic and hypidiomorphic granular texture and containing structure.③The magnetite dissemination with particle size between 0.2 mm and 0.045 mm accounting for 65% is divided by quartz and hornblende，while 20% with particles size between 0.025 mm and 0.045 mm is distributed in gangue minerals，disseminated with sparse and dense，about 10% between 0.01 mm and 0.025 mm and 5% under 0.01 mm.Therefore，the process of dry pre-magnetic separation-stage milling and grinding-stage low intensity magnetic separation is recommended.On the basis of recovery early and reducing excessive grinding，the recovery of magnetite with particle size under 0.025 mm should be strengthened to ensure the recovery rate of magnetite.

Key words: Magnetite, Structure and texture, Dissemination particle