©　2017,　Editorial　Office　of　Opto-Electronic　Engineering.　All　right　reserved.Three　dimensional　(3D)　metamaterials　are　periodic　artificial　microstructures　arranged　in　three-dimensional　space.　They　are　in　scale　of　subwavelength,　thus　getting　extraordinary　physical　properties　which　are　not　found　in　nature.　The　recent　developments　on　basic　theory　and　manufacturing　process　of　the　3D　metamaterials　are　discussed　in　this　letter.　Manufacturing　processes　of　the　3D　metamaterials　are　sorted　out,　including　printing　circuit　board　and　assembly,　machining　technology,　3D　printing　technology,　micro/nano-manufacturing　technology.　As　the　representative　devices　of　3D　metamaterials,　the　electromagnetic　cloaks,　lens　antennas,　absorbers　and　flexible　metamaterials　are　discussed　to　show　how　the　3D　metamaterials　control　the　electromagnetic-wave.　Devices　of　left-handed　metamaterials,　graded　refractive　index　metamaterials,　intelligent　metamaterials　are　also　discussed.　Finally,　the　development　trends　of　3D　metamaterials　in　future　are　discussed　and　predicted　according　to　the　present　problems　of　3D　metamaterials.