In recent years，weak-base ternary compound system has been adopted by Daqing oilfield to replace strong-base ternary compound system，which not only overcomes the scaling problem at the production end，but also enhances oil recovery. Compared with the strong-base ternary compound system，the research of weak-base ternary compound system starts late，and some chemical flooding mechanism needs to be further explored. Taking the reservoir and fluid in northern Saertu of Daqing oilfield as experimental object，the transmission and migration capacity and deep fluid diversion ability of weakbase ternary compound system and its impact on increasing oil production and decreasing water cut were researched by means of instrument detection，chemical analysis and physical simulation guided by physical chemistry，polymer materials and reservoir engineering. Seepage resistance，shunt rate and oil recovery were the evaluation indexes. Results show that polymer concentration and carbonate micro particle number are the main factors which have influence on the transmission and migration capacity of the weak-base ternary compound system. Under the condition of the same viscosity，the deep fluid diversion ability of weak-base ternary compound system is reduced with the decrease of interfacial tension. However，under the condition of the same interfacial tension，it is enhanced with the increase of viscosity. The performance characteristics of weak-base ternary compound system can be evaluated by the transmission and migration capacity and deep fluid diversion ability from different aspects. Only when the two properties and reservoir properties achieve a reasonable match，the weak-base ternary compound system can obtain the best technical and economic results.