Calycanthus chinensis is a critically endangered species.There exist only two natural populations in eastern China.The plant was introduced into Tianmu Mountain National Nature Reserve from Shunxi population for esc situ conservation,and later the source population was incorporated into the Qingliangfeng National Nature Reserve for in situ conservation.In this study the genetic diversity of the species was assessed in comparison with Chimonanthus zhejiangensis to evaluate the result of conserving the genetic diversity of this species in nature reserves.The allozyme diversity in C.chinensis (He=0.0240 and I=0.0405) was no more than one fifth of that in Ch.zhejiangensis (He=0.1424 and I=0.2190) on the basis of 23 enzyme loci.The results of allozyme analysis were confirmed by ISSR markers.Of 103 bands,six (5.83％) were polymorphic at specific level (He=0.0188 and I=0.0275) and four were polymorphic within Shunxi population.No variation was detected within Longxi population and the Tianmu Mountain conserved population.However,considerable variations were detected in Ch.zhejiangensis (He =0.2240 and I =0.3326).Failure to detect any genetic variation within the conserved population at the Tianmu Mountain National Nature Reserve suggests that early ex situ conservation of C.Chinensis cannot be considered successful.Diminishing in size of Shunxi population in Qingliangfeng National Nature Reserve in the past seven years also implies that management of nature reserves in China ought to he improved for effective conservation of genetic diversity based on a better understanding of ecological requirements and population biology.