To　develop　novel　tumor　cell　microenvironment　stimuli-responsive　smart　controlled-release　delivery　systems　is　one　of　the　current　common　interests　of　materials　science　and　clinical　medicine.　Meanwhile,　mesoporous　silica　nanoparticles　as　a　promising　drug　carrier　have　become　the　new　area　of　interest　in　the　field　of　biomedical　application　in　recent　years　because　of　their　unique　characteristics　and　abilities　to　efficiently　and　specifically　entrap　cargo　molecules.　This　review　describes　the　more　recent　developments　and　achievements　of　mesoporous　silica　nanoparticles　in　drug　delivery.　In　particular,　we　focus　on　the　stimuli-responsive　controlled-release　systems　that　are　able　to　respond　to　tumor　cell　environmental　changes,　such　as　pH,　glucose,　adenosine-5＇-triphosphate　(ATP),　glutathione　(GSH),　and　H2O2.　Copyright　(C)　2014,　Food　and　Drug　Administration,　Taiwan.　Published　by　Elsevier　Taiwan　LLC.　All　rights　reserved.