Abstract: Emmenopterys henryi is a national Class II protection plant endemic to China.It is mainly distributed in the forest of subtropical middle or low mountain areas of Jiangxi province,Anhui province,etc.Based on the investigation in Wuyishan Nature Reserve,the population dynamics of E.henryi in four types of communities was studied.The diameter structure was calculated,the life table was established and the population dynamics of it was predicted by spectral analysis method.At the same time,the relationship between E.henryi population structure and environment factors was analyzed.The result showed that the population of E.henryi in Wuyishan Nature Reserve belonged to a declining one because of the less young seedlings.The population density was different in various habitats.The biggest population(8.45±0.818 individuals·100 m^-2)was the E.henryi pure stands.Its’ seedling number was 1.05±0.326 individuals·100 m^-2 more than that of others.While the least one was in the forest mixed with conifers and broad-leaved trees,the average population density was 6.58±0.76 individuals·100 m^-2,and no seedlings were in it.There was higher death rate in medium tree,but lower in others.The spectral analysis of the population dynamics of E.henryi was made,which revealed that a marked regularity of periodic fluctuation was in the process of natural regeneration.Analysis on 13 ecological factors,we found that higher light,higher soil moisture,weak acidic soil,more soil organic matter,higher temperature,higher humidity,and appropriate human disturbance may produce positive influence on the population increase of E.henryi,while high altitude,shady slope,big slope digree and high-coverage of plant may have negative effect on it.In situ conservation should be taken as the most important management by making the best use of characteristic of E.henryi,and especially the mother trees which were in the fruit-bearing stage must be protected in order to promote their natural regeneration.In addition,the seed collecting and seedling nursing measures should be carried out in the original habitats of E.henryi,to expand artificial population number of it.