Disclosed is a process for treating a reaction solution containing a long chain dicarboxylate. The process is characterized by comprising: acidifying a reaction solution so as to convert the long chain dicarboxylate into a long chain dicarboxylic acid, adding an extractant so as to extract the resulting long chain dicarboxylic acid, separating the phase rich in the long chain dicarboxylic acid, and further separating the long chain dicarboxylic acid. The process of the present invention has the following advantages: 1) the processing route is simple, the operation time is short, less equipment is required, and the production efficiency is high; 2) product yield is high; 3) product quality is good, purity in the resulting products is high, and the color is lighter; and 4) no active carbon is consumed and the solvent can be recycled, thereby saving resources and being environmentally friendly.