Abstract: With HDEHP as an extractant and xylene as a solvent, the separation of)~142)La from fission products by solvent extraction is studied. Based on twice Ba-La extraction separations performed after proper delay time("twice delay separation method"),a one-hour separation procedure is designed and examined. The chemical recovery of)~142)La is about 80%, and the decontamination factors for most γ-emitters) are higher than 1×10~3.