In this study, a ternary cationic polyacrylamide with the hydrophobic characteristic was prepared through Ultraviolet (UV)-initiated polymerization technique for the estrone (E1) environmental estrogen separation and removal. The monomers of acrylamide (AM), acryloyloxyethyl-trimethyl ammonium chloride (DAC) and acryloyloxyethyl dimethylbenzyl ammonium chloride (AODBAC) were used to synthesize the ternary copolymer (PADA). Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance spectroscopy (1H NMR), thermogravimetry/differential scanning calorimetry (TG/DSC) and scanning electron microscopy (SEM) were employed to characterize the structure and thermal decomposition property of the polymers, respectively. FT-IR and 1H NMR results indicated the successful formation of the polymers. Besides, with the introduction of hydrophobic groups (phenyl group), a favorable thermal stability of the PADA was observed by TG/DSC analyses. At the optimal condition (pH=7, flocculant dosage= 4.0 mg/L), an excellent E1 flocculation performance (E1 removal rate: 90.1%, floc size: 18.3μm and flocculation kinetics: 22.69×10-4 s-1) was acquired by using the efficient flocculant PADA-3 (cationic degree= 40%, and intrinsic viscosity = 6.30 dL.g-1). The zeta potential and floc size analyses were used to analyze the possible ?occulation mechanism for the E1 removal. Results indicated that the charge neutralization, adsorption and birding effects were dominant in the E1 removal progress.