Moringa oleifera Lam. is a Moringa genus in the Moringaceae family that is high in nutrients and has a wide range of applications. Phenolic compounds are widely found in plants and have various health benefits for the human body. With its high content and wide variety of phenolic compounds, M. oleifera Lam. has been widely studied for its health benefits. The phenolic compounds in M. oleifera Lam. (MOPCs) can be a potential source of functional food ingredients in pharmaceutical and industrial applications. Numerous studies have shown that MOPCs have antioxidant, anti-obesity, anti-diabetic, and antibacterial effects. Although the research on MOPCs has been gradually increasing, the extraction, isolation, identification, biological activities, and comprehensive application of MOPCs need a more systematic summary and generalization. Therefore, this paper reviews the isolation and extraction methods, structure identification, biological activities, and comprehensive applications to provide a further reference for the research and application of MOPCs.