Abstract: Extracellular vesicles are spherical nanovesicles characterized by a bilayer phospholipid structure, released by various cell types, which are increasingly recognized as important mediators of intercellular communication via transfer of a wide variety of molecular cargoes, including proteins, nucleic acid, lipids and metabolites. Extracellular vesicles are also secreted by microalgae, which play important roles in intercellular communication, including maintain the biological environment homeostasis, control flows of nutrients and energy, influence virus infection and regulate the balance of aquatic ecosystem. This article aims to comprehensively review the concepts, isolation and enrichment methods, biological characteristics and physiological functions of microalgal-derived extracellular vesicles. We summarize the advantages and disadvantages of the common methods for purifying and detecting microalgae-derived extracellular vesicles. The fundamental structure, features and bioactivities of these EVs are also summarized, and the potential and advantages of these nanoparticles as therapeutics and nanodrug delivery platform are further discussed. Furthermore, we discuss opinions and suggestions regarding significant existing challenges and future prospects in the manufacturing of microalgal-derived extracellular vesicles for drug delivery platform. It will provide a theoretical support for exploring the biological functions and approaches of microalgal-derived extracellular vesicles in both microalgae and medical industry. Our findings suggest that the research on production of microalgal-derived extracellular vesicles and their application in construction drug delivery systems is poised to become a future trend in the microalgal application field.