After 0.5 PV polymer flooding of Xiaermen H2IV block formation，the distribution of the remaining oil is more scattered. In order to optimize a chemical flooding method with low cost and great enhancement of oil recovery，based on the analysis of the occurrence form and crude oil composition of the remaining oil in the block，according to the effects of different chemical flooding methods on the residual oil of different forms，the multi-slug combination flooding was determined for this block. The experimental results showed that，the optimized binary composite flooding system，composed of 2000 mg/L surfactant B-2 and 1500 mg/L polymer CJ-1，had good long-term thermal stability. After aging for 360 d，the interfacial tension could still maintain the order of 10-2 mN/m，and the viscosity retention rate was above 85% . At the same polymer concentration and permeability，the injection pressure of the binary system was lower than that of the polymer. When the polymer concentration was 1500 mg/L and the surfactant concentration was 500—5000 mg/L，the adsorption capacity of surfactant in the binary composite system was lower than that of a single surfactant system. When the concentration of surfactant was higher than 1000 mg/L，the oil washing efficiency of the binary system was higher than 40%. The results of the two-layer heterogeneous core flooding experiment showed that multi-slug flooding after polymer flooding could enhance the oil recovery by 21.9%，higher than that of single polymer flooding and binary composite flooding by12.69% and 5.33%，respectively. Finally，the utilization mode of remaining oil in this block was determined as a 0.05 PV profile control—0.35 PV polymer flooding—0.15 PV binary composite flooding—0.05 PV profile control multi-slug combined displacement at low cost with polymer flooding as the main and binary compound driving and profile control as the auxiliary.