The traditional research on the seepage 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 in 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 90℃ and total salinity 58002 mg/L brine. Meanwhile, the oil displacement efficiency and residual oil distribution of conventional binary and temperature-resistant salt-tolerant binary systems were studied. The research results show that: with the increase of migration distance, the viscosity of the system gradually decreases, and the viscosity loss is more in the early stage of injection. After a certain distance of migration, the viscosity loss gradually levels off. With the increase of injection volume, the viscosity of the system shows a gradient distribution, and the peak of the viscosity curve continues to shift to the right. The oil displacement test results of conventional binary and temperature-resistant salt-tolerant binary systems show that the 0.6 PV conventional binary flooding system increases the recovery degree by 16.65%, while the 0.6 PV temperature-resistant salt-tolerant binary flooding system increases the recovery rate by 21.72%, which is 5.07 percentage points higher than the former, and 4.41 percentage points higher only in the 0.6 PV stage of chemical flooding. The residual oil distribution test results show that the startup effect of residual oil in the near-well zone (0-2 m) is good; in the middle of the model (3.33-7.33 m), the residual oil saturation of temperature-resistant salt-tolerant binary flooding increases; while in the deep part of the model (7.33-10 m), due to the serious loss of system performance, the residual oil saturation is significantly higher. From the perspective of residual oil saturation after oil displacement by the two systems, the temperature-resistant salt-tolerant binary system has better overall propulsion performance and mobility control ability; the injection of flooding system with large slug in homogeneous reservoir is more conducive to improving oil recovery.