Endohedral metallofullerenes (EMFs) have attracted a variety of research interests due to their unique cage-like embedded structures. Profiting from the protection of the carbon cage, the internal metal ion(s) or cluster of EMFs exhibit distinctive electronic structures and spin characteristics, which shows important potential applications in quantum information processing, high-density information storage and quantum control. This review mainly introduces the research progress of spin-active EMFs and analyzes their electronic structures and spin characteristics, and then discusses three techniques to manipulate the electron spin of EMFs, such as changing the temperature, modifying the carbon cage and constructing self-assembly system. Through investigating the electron spin behaviors of EMFs, we can probe the molecular motion state, and thus make a foundation for building EMFs-based quantum systems.