Novel hydrophilic-hydrophilic block copolymer with one block containing β-cyclodextrin was synthesized. Core-shell structured nano-assemblies with chemical sensitivity could be constructed by this copolymer in the presence of hydrophobic compounds. By selecting appropriate guest components, polyion complex micelles could also be assembled. These results suggest the potential versatile applications of this type of copolymers in pharmaceutics, nanomedicine, and nano-biotechnology.