Dressing iron from the primary ores is the hot topic all the way. In our study, one primary magnetite iron ore was selected to analyze the chemical composition properties, and micro-sturctures of the mineerals. The results show that magnetite is the main iron mineral taking up 25.1% of total, the Fe content in the lattice is 64.45%. Qualified iron ore concentrate would be obtained by using weak magnetic separation and desulfurization. However, the tiny magnetite may form complex dust particle, cloudiness or latticed structure and the close intergrowth with ilmenite, pyrrhotite and gangue minerals would not be fully separated even using fine milling which may definitely affect the grade of iron ore concentrate.