Aiming at the practical problems of high reservoir temperature，high salinity of formation water，high concentration of divalent cations of calcium and magnesium and high viscosity of formation crude oil in Shengli Oilfield，a novel polymer flooding system with strong tolerance to temperature，salinity，calcium and magnesium was designed to meet the needs of mobility control in polymer flooding in Class III of high-temperature and high-salinity heavy oil reservoirs. Based on the property evaluation of conventional polymers，a new property evaluation for the novel temperature-resistant and salt-tolerant polymer flooding system was improved，and the seepage law of the novel polymer in the core was summarized. Besides，the mobility control simulation of the novel polymer flooding was carried out by reservoir numerical simulation. Physical simulation experiment results show that the ability of resistance of the novel polymer to Ca2+and Mg2+was above 800 mg/L and the enhanced oil recovery by the physical simulation was more than 15.0%. Under the guidance of the reasonable mobility ratio limits，the enhanced oil recovery by the numerical simulation was 7.0%. A pilot test of polymer flooding was carried out in No.4 unit of Dong3 member in No.2 area of Shengtuo Oilfield. The composite water cut was decreased from 96.5% to 88.4% and the daily oil production was increased from 86 t/d to 273 t/d，which shows significant water cut decrease and oil production increase.