Abstract: In order to solve the problems of low reserves utilization caused by strong reservoir heterogeneity, high water injection intensity, water injection spurt and conventional profile control measures which could not be effectively carried out in a certain offshore oilfield, application of in-situ CO₂ generation enhanced oil recovery technology was investigated by physical model displacement experiment. Then the parameters such as injection volume, injection method, injection speed and the amount of stabilizer dosage were optimized. The results show that the recovery efficiency of in-situ CO₂ generation technology is remarkable. In the range of (200-10 000)×10^-3 μm² of reservoir permeability, oil recovery can be increased by 28.70%-32.29% on the basis of conventional water flooding, and in the range of 10-500 mPa·s of crude oil, viscosity has little effect on this technology. The optimum technological parameters are as follows: 1.0 PV injection rate, 8 slug injection, injection rate ratio of gas forming and gas yielding is 1:1, and the amount of stabilizer dosage is 0.1 PV. The field test shows that in-situ CO₂ generation enhanced oil recovery technology plays a significant role in stabilizing oil production and controlling water production on offshore oilfield. After adopting this measure, daily oil production increases 100 m³, water cut decreases 12%, and the net oil increases 3826 m³ in effective period.