Ganoderma lucidum polysaccharides possess unique functional properties. Various processing technologies have been used to produce and modify G. lucidum polysaccharides to improve their yield and utilization. In this review, the structure and health benefits were summarized, and the factors that may affect the quality of G. lucidum polysaccharides were discussed, including the use of chemical modifications such as sulfation, carboxymethylation, and selenization. Those modifications improved the physicochemical characteristics and utilization of G. lucidum polysaccharides, and made them more stable that could be used as functional biomaterials to encapsulate active substances. Ultimate, G. lucidum polysaccharide-based nanoparticles were designed to deliver various functional ingredients to achieve better health-promoting effects. Overall, this review presents an in-depth summary of current modification strategies and offers new insights into the effective processing techniques to develop G. lucidum polysaccharide-rich functional foods or nutraceuticals.