Abstract: A displacement system designed for robust heterogeneous oil reservoirs and its application within the oil exploitation field. System comprises a polymer-enhanced foam plugging agent and an active polymer flooding agent. Plugging agent consists of 0.12% bio-polysaccharide polymer diutan gum foam stabilizer and 0.4% ?-olefin sulfonate foaming agent by mass. The active polymer flooding agent is formulated through free radical polymerization, with components comprising a total monomer concentration of 27.5%, wherein monomer A to monomer B ratio is 7.5:2.5, monomer C constitutes 5.5% of the total monomer concentration, and water comprises the remaining. Monomer A is acrylamide, monomer B is 2-acrylamide-2-methyl propane sulfonic acid, and monomer C is a quaternary ammonium salt type active monomer. Demonstrated through parallel core displacement experiments, this displacement system exhibits effective displacement in heterogeneous oil reservoirs with a permeability gradation of 30 at 65° C.