Abstract: The effect of the content of citric acid on distribution ratio, separation coefficient and extraction capacity of Pr/Nd in the P204-RECl3-LA system was investigated. The di-(2-ethyl hexyl) phosphoric acid (P204) was used as an extraction solvent and a certain proportion of citric acid was added into the rare earth chloride (PrCl3 or NdCl3) solution in the presence of lactic acid. The results showed that the distribution ratio, separation coefficient and extraction capacity of Pr/Nd in the P204-RECl3-LA system containing citric acid are significantly higher than that of a single lactic acid system. The separation factor increases from 1.44 to 1.68 and the extraction capacity increases from 25.23 g/L to 28.53 g/L, which provides a theoretical and technical basis for the study of green cleaning extraction method of rare earth in the non-saponification extraction system.