Mesoporous carbon spheres are a new type of porous spherical carbon materials. They are promising in many fields such as biomedicine, energy storage/conversion, environmental treatment, and catalysis, thanks to their high surface area, good chemical stability, excellent biocompatibility, tunable pore sizes and volume, and controllable particle size distribution. In the present work, recent advances in the preparing methods of mesoporous carbon spheres, including templating methods, Stöber methods, and microfluidic droplets methods, are summarized. Moreover, the applications of mesoporous carbon spheres as drug delivery system(DDS) including controlled surface property release, stimuli-responsive release, targeted delivery, and theranostic delivery, are reviewed. Finally, the main problems and development trends in the synthesis of mesoporous carbon spheres and applications in DDS for cancer therapy are proposed and discussed.