Abstract: Carboxymethyl cellulose (CMC), as a widely available, non−toxic, and biodegradable anionic polymer derivative, is extensively utilized as a green inhibitor in mineral flotation. However, unmodified CMC exhibits limitations such as insufficient selectivity, limited inhibition efficacy, and poor adaptability to complex pulp environments. Addressing these shortcomings, this paper systematically reviews the mechanisms and technical characteristics of three modification approaches—physical modification, chemical modification, and enzymatic modification—and compares their effectiveness and applicable scenarios. It also summarizes the applications of common characterization techniques—including Fourier transform infrared spectroscopy (FT−IR), X−ray photoelectron spectroscopy (XPS), Zeta potential measurement, and scanning electron microscopy (SEM)—for structural analysis and interface interaction studies. The study focuses on advancements in using modified CMC as a gangue inhibitor in flotation processes, elucidating its selective inhibition mechanism through synergistic effects of hydrogen bonding, electrostatic adsorption, chemical chelation, and metal ion bridging. Additionally, it outlines applications of modified CMC as collector agents, flocculants, scale inhibitors, and pellet binders. Finally, the paper explores future trends in precise functional group modification, cost−effective green synthesis, and industrial−scale application of modified CMC, aiming to provide theoretical insights and technical support for developing efficient green flotation reagents and improving complex mineral separation processes.