Abstract: Postbiotics are preparations of inanimate microorganisms and/or their constituents that benefit the host's health. These constituents include inactivated bacteria and their metabolites (e.g., peptidoglycans, teichoic acids, extracellular polysaccharides, surface layer proteins, etc.) as well as bacteria's metabolites (e.g., short-chain fatty acids, extracellular polysaccharides, organic acids, proteins, etc.). Postbiotics are safer and more stable than probiotics, and they can prevent the transmission of drug-resistant genes from living bacteria. They are also more suitable for production and storage. This study combines the most recent domestic and international research contents to elaborate on the postbiotic research hotspots, functional components and bioactivities of postbiotics, plant-based postbiotics components and bioactivities, and the industrial status and trends of postbiotics. It introduces in detail the progress of the research on the components of postbiotics in the areas of antioxidant, immunomodulation and anti-inflammation that have been researched, with a particular focus on plant-based postbiotics components. Through the outlook of the future development trend of the postbiotic market, the necessity of establishing the safety research and evaluation system of postbiotics is elaborated. This review will provide a reference for in-depth research on postbiotics and their industrialization and development in the field of food biomedicine and other fields.