The dynamic interfacial tensions between four organic alkalis solutions（ethanolamine，N，N-dimethyl ethanolamine， dimethylamine，1，6-Hexylenediamime）and shengli crude oils in two different blocks were investigated，and also the different interactions between three inorganic alkalis solutions（NaOH、NaHCO₃、Na₂CO₃）and crude oils were compared. The experimental results showed that linearorganic alkali ethanolamine could react with petroleum acid，reducing the interfacial tension seffectively， and could lower interfacial tension to ultra-low value at pH value of 12. However，the organic alkalis with larger molecular size showed the weaker abilities of lowering interfacial tension. At the same time，the interaction between organic alkali and the crude oils were strongly influenced by the content and structure of petroleum acid. The inorganic alkali had the same abilities to reduce the interfacial tensions as the ethanolamine. Moreover，the weaker the alkalinity of the inorganic alkali，the lower pH value needed to react with crude oil.