Janus polymeric cages are fabricated by Pickering emulsion interfacial polymerization. The modified silica particles are used to stabilize the emulsions. Oil-soluble monomers and water-soluble monomers copolymerized in between the voids among the silica particles at the interface, forming amphiphilic Janus polymer shell in which the silica particles are embedded. After removal of the silica particles and the oil core, the corresponding Janus polymeric cages are achieved with uniform and regularly arrayed holes across the shell. The Janus cages are permeable to both organic molecules and particles.