Two kinds of chemical modified β-cyclodextrin(β-CD) with different acylation degree were synthesized relying on the content of chloroacetyl chloride agent used．The structures of β-CD with different degree of acylation were characterized using infrared spectroscopy．13C-NMR

1H-NMR and titration analysis．Infrared spectroscopy and 13C-NMR indicated that acylations occurred at C-2 and C-6 position in β-CD

1H-NMR and titration analysis suggested that the acylation degrees of β-CD are 3.2 and 4.5

respectively．A series of star polymers having different average length of poly (N

N-dimethylaminoethyl methacrylate) were synthesized by atom transfer radical polymerization (ATRP) using anterior acylated β-CD as the initiator．The branch chain structure and their compositions were characterized using infrared spectroscopy

1H-NMR

element analysis and DSC．The star polymers prepared here had a hard 1CD core with the potential to form inclusion complexes with certain small organic compounds

and also their aqueous solutions were studied by UV spectroscopy in order to explore their thermo- and pH sensitivities．The results showed that the novel star polymers exhibited clearly thermo- and pH respondings in accordance with the change of the environment．