The Zhujiachong eclogite in the southeastern Dabieshan UHP terrane was originally taken as low-temperature and high-pressure (LT-HP) eclogite, or ‘cold’ eclogite. Coesite pseudomorphs, however, subsequently indicated that it has experienced ultra-high pressure (UHP) metamorphism. In this study we analyze the retrograde amphobolite facies mineralogy of the eclogite by 40Ar/39Ar laser stepwise heating, UV-laser ablation microprobe and in vacuo crushing techniques employed to determine the ages of discrete minerals and the symplectite matrix of the eclogite. The 40Ar/39Ar apparent ages indicate that UHP phengite formed before 265 Ma. Amphibolite-facies retrograde metamorphism took place from 242 Ma to 217 Ma, and from 217 Ma to 200 Ma hydrothermal activity led to the formation of coarse-grained paragonite and fluid inclusions in vein amphibole.