How to efficiently extract lithium resources from raw ore plays an important role in promoting the development of new energy fields dominated by lithium. Therefore, this paper proposes a co-flotation process for lepidolite and spodumene. The process involves synergistic alkaline corrosion treatment synergistic with magnesium (Mg2+) ion activation. Micro-flotation experiments had proven the high efficiency of the process for recovering the two main lithium-containing minerals in this paper. Alkaline corrosion and Mg2+ synergistic action could effectively promote the adsorption of the collectors on the mineral surface using adsorption capacity detection, X-ray photoelectron spectroscopy detections, and zeta potential measurement. At the same time, there were adsorption differences between the two minerals under different treatment conditions. Additionally, the influence of alkali corrosion conditions on the morphology of the two minerals, the flocculation state after synergistic activation, and the mechanism and difference of adsorption morphology were explored through particle size analysis, scanning electron microscope measurements, energy dispersive spectrometer detection, and atomic force microscope detection.