In order to understand the interaction rule between alkali and crude oil，the Gudong crude oil is separated into acidic components，resin and asphaltene，saturated hydrocarbons，aromatic hydrocarbons.The Gudong crude oil as the study object has high acid value.The interfacial tension between the aqueous solution of alkali and simulated oil is investigated through changing the alkali type and value of pH.The result shows that the rule of organic alkali decreasing interfacial tension is different from that of inorganic alkali.With the increase of pH，the interfacial tension between organic alkali and Gudong crude oil decreases at first and then increases.When the organic alkali concentration is 1%，the interfacial tension is lowest.The dynamic interfacial tension between acidic component simulation oil and the aqueous solution of organic alkali varies with time，and the interfacial tension-time curve shows the shape of“V”or “U”.Through the variation of interfacial tension between aqueous solution of organic alkali and resin simulated oil and asphaltene simulated oil，it can be seen that the organic alkali can react with the acidic components in resin and asphaltene.However，the organic alkali can’t react with saturated hydrocarbons and aromatic hydrocarbons.