As for the difficulties in the water injection profile controlling in the offshore oilfields, a kind of polyacrylamide emulsion and its relative profile controlling system were developed in this study. Laboratory experiments have shown that the dissolution time of the emulsion polymer into the sea water is less than 15 minutes, and the viscosity of the polymer solution is larger than 15 mPa·s when the polymer concentration is 2000 mg/L under the temperature of 70°C. The viscosity of the polymer crosslinking system is larger than 150 mPa·s, and the modulus elasticity of the crosslinking system is larger than 500 mPa. A pilot test on two wells from the Shengli Chengao Oilfield was conducted to verify the practical application performance of the emulsion polymer. The pilot test shows that after 2 months emulsion polymer injection, the bottomhole pressure of the production wells has increased by 1.48-1.79 MPa, the oil production from one correspondent well has increased from 28.67 t/d to 35.8 t/d, and the water content in the production flow has decreased from 52.3% to 41.7%. It is believed that the developed emulsion polymer and its crosslinking system have a wide application to the development of Shengli offshore fields.