In recent decades, there has been a growing interest in the use of polysaccharides that exhibit biological activity for a wide range of innovative applications. This is due to their nontoxicity, biodegradability, biocompatibility, and therapeutic properties. The diverse properties of polysaccharides derived from marine algae make them a promising strategy for the construction of drug delivery systems (DDSs). Marine algal polysaccharides can be utilized in regenerative medicine and gene delivery to facilitate the controlled release of therapeutic substances, which is a critical stage in the fight against severe diseases. Algal polysaccharide-based nanoparticles, microspheres, hydrogels, patches, and films are among the numerous controllable and sustained anti-inflammatory and anticancer DDSs that can be used due to the biological activities of these algal polymers. This review paper summarizes the advantages and applications of marine algal polysaccharides in DDSs (such as nanoparticles, microspheres, hydrogels, patches and films) as well as recent advances in drug delivery technologies, thereby providing valuable information for future research on drug delivery-based algal polysaccharides.