China is rich in titanium resources, but low-grade ilmenite accounts for a relatively high proportion, and has the characteristics of fine dissemination size and complex symbiotic relationship, which leads to difficult beneficiation and low comprehensive utilization rate of resources. The modification mechanism of microwave pretreatment on the physical and chemical properties of ilmenite surface is not clear, and there is a lack of systematic verification of multiple characterization methods, which cannot explain the essential reason for the improvement of microwave-induced flotation efficiency. Therefore, in this paper, the process of microwave pretreatment is used to treat ilmenite, and the flotation test of pure mineral is carried out to explore the influence mechanism of microwave pretreatment on ilmenite flotation. The efficiency of octyl hydroxamic acid (OHA) and heptyl diphosphonic acid hydrochloride (HDPA) as collectors in the flotation separation of ilmenite and quartz was systematically investigated. Through the flotation test of pure minerals, it was found that the flotation effect of ilmenite was better than that of single reagent when OHA and HDPA were used in a molar ratio of 3:1. Microwave pretreatment can selectively enhance the floatability of ilmenite. After 180 s treatment, the recovery rate is increased by 6.85 %, and the amount of collector is reduced by 28.57 %, but it has no significant effect on quartz. By means of X-ray diffraction spectroscopy (XRD), scanning electron microscopy and energy dispersive spectroscopy, X-ray photoelectron spectroscopy (XPS) and specific surface area and pore test (BET), it was found that microwave treatment did not change the phase of ilmenite, but caused the weakening of the crystal plane structure, the formation of microcracks and pores on the surface, showing a similar 'erosion 'morphology. The specific surface area increased from 0.2537 m²/g to 0.4557 m²/g, indicating that the specific surface area of ilmenite could be effectively increased, which provided more active adsorption sites for the adsorption of collectors, which was beneficial to adsorb more collector molecules, increase the adsorption density, and improve the hydrophobic properties of ilmenite surface to a greater extent. XPS results further showed that Fe²⁺ on the surface was partially oxidized to Fe³⁺, and the content of Fe³⁺ increased from 23.91% to 38.64%. As a better coordination center, Fe³⁺ forms a more stable and denser hydrophobic layer with chelating collectors OHA and HDPA, which significantly improves the flotation efficiency and reduces the reagent consumption. This study reveals the physical and chemical mechanisms of microwave activation promoting ilmenite flotation, and provides a theoretical basis for efficient separation of ilmenite.