In the offshore Chengdao oilfield, the oil reservoir of Guantao member is consisted of high porosity and permeability sandstone. Due to the high speed oil development, the water cut increased quickly. In this paper, we used the elastic microspheres of seawater based to evaluate the matching relationship between the pore-scale and the feature of elastic-microspheres, the viscosity, and the double-tube driving test. The results suggested that the initial particle size of the elastic-microsphere is 1/3-1/7 times of the pore diameter, after 10-15 days, the microsphere particle size expands to 1.4-1.5 times of the pore diameter, which can plug the pore effectively.The initial viscosity of the microsphere solution is about 1 mPa ? s, that can come into the layer deeply. It is applied in CB25A test area with online mode for deep profile controlling technology. After 0.01 times pore volume flooding injection, the well’s water pressure increased by 1-2 MPa, and the full-deep improved by 0.22-0.57. In the corresponding 11 wells, 9 are enhanced by this technique, and the average water cut is reduced by 7.6%, moreover, the recovery performance is still enhanced even after 4 years of subsequent water flooding. The elastic-microspheres of deep flooding to the oil stabilization and water control of offshore oilfield are of durable performance.