As a very important antioxidant enzyme in vivo,selenoenzyme plays a very important role in maintaining the metabolic balance of reactive oxygen species(ROS)and protecting body from oxidative stress.The artificial simulation of selenoenzyme especially the construction of environmental-responsive smart artificial enzymes can reveal the catalytic mechanism of nature enzyme and expand the potential applications in the development of antioxidant drugs.In this research,compound V was designed and synthesized.The new organic selenium compound contained both selenoenzyme catalytic center and two secondary amine groups.Two secondary amine groups were both protonated at pH=6.The compound V can assemble with cucurbit［6］uril(CB［6］)to form molecular machine.The active center was encapsulated in the hydrophobic cavity of CB［6］so that almost no catalytic activity can be shown［(2.1±0.06)×10^-5μmol·min-1·μmol^-1］.The protonation degree of two secondary amine groups had a significantly decrease at pH=8 which lead to the partly dissociation of molecular machine.The active center was exposed to solution at this time and the catalytic activity was (0.31±0.01)×10^-3μmol·min^-1·μmol^-1.Therefore,pH-responsive artificial selenoenzyme can be successfully constructed by the association and dissociation of molecular machine through the changing the pH between 6 and 8 in order to control the recombination and partial dissociation of molecular machines.