In order to microscopic study mechanism and oil recovery efficiency of oil displacement of polymeric surfactant，the micro-etching simulation model was used to carry out the oil displacement experiment，and the result was compared with that of core flooding experiment. The results showed that in the microscopic oil displacement experiment，six types of residual oil were produced in the model after water flooding. Flooding effect was not obvious that polymeric surfactant displaced residual oil at blind end. The mechanism of oil displacement of polymeric surfactant was viscosity-increasing effect，viscoelastic effect and emulsification，which could expand swept volume，reduce percolating resistance，and pull and squeeze residual oil to emulsify large oil droplets into small oil droplets，respectively. Therefore，the residual oil was effectively displaced. Comparing the microscopic model with the core flooding experiment，the oil recovery efficiency was basically consistent. When the concentration of polymeric surfactant was higher，the ability of displacing residual oil was stronger and the oil recovery was better. When the concentration of polymeric surfactant was 2000 mg/L，the oil recovery efficiency was the best and the enhanced oil recovery was 19.69%.