Amphiphilic polymers were synthesized using butadiene (PB) with a hydrophobic structure and acrylamide (AM), acrylic (AA), 2-acrylamide-2 methylpropane sulfonic acid (AMPS) with a hydrophilic structure. The benzene ring structure in the polymer chains can be embedded in the dense structure of the heavy oil asphaltenes. The hydrophilic groups on the polymer chains inside the heavy oil can promote the formation of O/W emulsions, thereby reducing the viscosity of the heavy oil. The IR, TG, and GPC characterization results of the polymer indicate that all four monomers AM, AA, AMPS, and PB have participated in the copolymerization. The higher pyrolysis temperature (250 ℃) ensures the thermal stability of the viscosity reducing agent, and the lower molecular weight (8×10⁴～10×10⁴) is helpful for the viscosity reducer to enter the “inside” of the heavy oil. With Suizhong 36-1 degassed heavy oil (SZ) and Bamianhe heavy oil (BMH) in Jianghan Oil Region as viscosity reduction target, when the viscosity reduction agent is under certain conditions (70 ℃, the mass fraction is 0.5% and 0.6% respectively), the viscosity reduction rates of the heavy oil are 86.14%and 83.85%, respectively, showing that amphiphilic polymers have excellent viscosity reduction effects. Under certain conditions (70 ℃, mass concentration is 0.5%), reducing the oil-water volume ratio (less than 6∶4) can effectively improve the viscosity reduction effect.