As for alkali-surfactant-polymer system，the problem of the chemical flooding agent retention in reservoir and the resulting chromatographic separation phenomenon，is the hot-button issue among petroleum science and technology personnel. According to field actual demand，the oil displacement agent properties and its variation regulation in reservoir was researched during the course of alkali-surfactant-polymer flooding with strong base at artificial core containing natural sands with the length of 18 m，based on the geological and fluid characteristics in reservoir of Daqing Lamadian oilfield. The results showed that，comparing with polymer，the relative molecular mass of surfactant and alkali is smaller，so the inaccessible pore volume was smaller，their swept volume was larger，their liquid retention was larger and their breakthrough time was later，which led to chromatographic fractionation phenomenon among the three parts，and weakened their synergistic effect in oil displacement process. During the injection process of alkali-surfactant-polymer composite system，when the injected slug size was up to 0.482—0.543 PV，the interfacial tension could reach to a magnitude of 10^-2 mN/m within the whole length of the core and reach to a magnitude of 10^-3 mN/m in the local area. During the transmission and migration process of alkali-surfactant-polymer composite system in the artificial core，the polymer molecular coil dimension decreased due to the pore shear effect，the viscosity of the system gradually reduced from injection side to produced end，as a result，the viscosity loss rate of produced end was as high as 69%. At the end of succeeding water flooding，the residual oil saturation and the retention of surface active agent in the core gradually reduced from injection side to produced end，and the residual oil saturation was of 58% and the retention of surface active agent was of 0.6462 mg/g at the produced end.