The traditional research on the seepage characteristics of polymer flooding systems mostly adopts static adsorption method and small model method. The chromatographic separation phenomenon is not obvious，which cannot reflect the real seepage law of the reservoir. In order to study the real migration law of the new temperature-resistant and salt-tolerant binary flooding system in the Class Ⅲ reservoir of Shengli oilfield，a 10 m ultra-long sand-packed model was used to investigate the dynamic performance changes and long-distance migration of the binary system under the conditions of reservoir temperature of 90 ℃ and salinity of 58 002 mg/L. Meanwhile，the oil displacement efficiency and residual oil distribution of conventional binary and temperature-resistant salt-tolerant binary systems were studied. The research results showed that，with the increase of migration distance，the viscosity of the system gradually decreased，and the viscosity loss was greater in the early stage of injection. After a certain distance of migration，the viscosity loss gradually leveled off. With the increase of injection volume，the viscosity of the system showed a gradient distribution，and the peak of the viscosity curve continued to shift to the right. The oil displacement test results of conventional binary and temperature-resistant salt-tolerant binary systems showed that the 0.6 PV conventional binary flooding system enhanced oil recovery degree by 16.65 percentage point，while the 0.6 PV temperature-resistant salt-tolerant binary flooding system enhanced oil recovery by 21.72 percentage point，which was 5.07 percentage points higher than the former，and 4.41 percentage points higher in the 0.6 PV stage of chemical flooding. The residual oil distribution test results showed that the startup effect of residual oil in the near-well zone（0—2 m）was good；in the middle（3.33—7.33 m）of the model，the residual oil saturation of temperature-resistant salt-tolerant binary flooding increased slightly；while in the deep part（7.33—10 m）of the model，due to the serious loss of system performance，the residual oil saturation was significantly higher. From the perspective of residual oil saturation after oil displacement by the two systems，the temperature-resistant salt-tolerant binary system had better overall propulsion performance and mobility control ability；the injection of flooding system with large slug in homogeneous reservoir was more conducive to enhancing oil recovery.