This study investigated a hydrophobic-modified cationic polyacrylamide (PAMP) synthesized through low-pressure UV-initiated copolymerization by using monomers of acrylamide (AM), diallyl dimethyl ammonium chloride aqueous solution (DADMAC), and dodecyl polyglucoside (DPL) to effectively remove emulsified oil from water. Various analytical methods were used to characterize the microstructure of PAMP, including Fourier transform infrared spectroscopy (FTIR), unclear magnetic resonance (C-13 NMR and H-1 NMR), and thermal gravimetric and differential analysis (TG-DTA). Results confirmed that cationic and hydrophobic monomers were successfully grafted onto the molecular chain of the PAMP. Furthermore, the flocculation efficiency of PAMP was evaluated and optimized in emulsified oily wastewater treatment. PAMP exhibited satisfactory emulsified oil removal efficiency, and optimal oil and turbidity removal efficiencies of 94.5-98.6% and 95.1-98.9% were achieved with DADMAC content of 40%, DPL content of 30%, dosage of 8.5-9 mg/L, pH of 6-8, rapid stirring speed of 400 rpm, rapid stirring time of 35 min, slow stirring time of 15 min, and standing time of 25 min. Moreover, charge neutralization and hydrophobic association interaction dominate the emulsion breaking in oily wastewater flocculation.