Based　on　the　radiation　field　of　the　magneto-electric　dipole　antenna,　we　propose　a　novel　method　for　constructing　a　variable　three-dimensional　(3D)　optical　cage　without　complex　optimization,　which　further　improves　the　efficiency　of　optical　operations　and　is　easier　to　implement.　Numerical　results　show　that　the　method　generates　dark　regions　with　orderly　varying　sizes,　and　their　shapes　can　achieve　a　perfect　spherical　configuration.　Such　variable　optical　cages　will　facilitate　the　capture　of　different　particles　and　atoms.　©　2023　IEEE.