本文研究了吡啶－２．６－双酰代－３－甲基－１－苯基－５－吡唑啉酮（ＰＤＣＢＰ，Ｈ２Ａ）对部分稀土离子的萃取行为，用多种分析测试方法证实其萃合物的组成和由稀土直接与萃取剂（Ｈ２Ａ）反应制得的固体配合物组成相同，ＲＥ（ＨＡ）２ｃｌ．它是通过吡啶氮原子和烯醇氧原子对稀土离子配位的，形成带有Ｏ—ＲＥ—Ｎ键的５元环和Ｏ—ＲＥ—Ｏ键的六元环的螯合物，使配合物比单纯含Ｏ—ＲＥ—Ｏ螯环的配合物稳定性有所增强． In this paper, the extraction of some rare earth ions by pyridine-2,6-bis-acyl-3-methyl-1-phenyl-5-pyrazolone (PDCBP, H2A) The composition of the complex and the composition of the solid complex prepared by the reaction of rare earth directly with the extractant (H2A) are the same, RE (HA) 2cl. It is through the pyridine nitrogen atoms and enol oxygen atoms of the rare earth ions coordination to form a 5-membered ring with O-RE-N bond and O-RE-O bond six-membered chelate complex, so that the complex It is more stable than the pure O-RE-O chelate complex.