In the paper, β-CD has been acidylated by 2-Bromoisobutyryl bromide to synthesize macromolecular initiator β-CD-BIBB. Then cationic star polymers have been prepared via ATRP by using AM and DMAEMA as comonomers, β-CD-BIBB as macromolecular initiator, bpy as complexant and CuBr as catalytic. FT-IR , 1H-NMR, DSC and TG were used to characterize initiator and cationic star polymer.