In order to reveal the survival potential and endangered mechanism of alpine Rhododendron species, we conducted the studies of population structure and dynamics on two natural populations of Rhododendron rex subsp. rex, which is a rare and endangered plant that endemic to southwest of China, based on field survey. The age structure and static life tables of R. rex subsp. rex were established, and the survival, mortality and vanish curves were plotted to character the species population structure. Meanwhile, the population dynamics were predicted by the results of a time sequence model and the quantitative dynamic index. The results indicated that: (1) the lack of the age classⅠ~Ⅱ was occurred in both Jiaozi snow Mountain (JM) and Xiaobaicaoling Mountain (XM) populations. Although the populations showed a stable type, both populations of R. rex subsp. rex were sensitive to external disturbance. (2) The population survival curves of JM and XM populations were trended to the DeeveyⅡ type. The life expectancy of R. rex subsp. rex was the highest in size class Ⅰand Ⅱ. The change trend of mortality curve is consistent with the vanish curve in each population. However, this change was different between the two natural populations of R. rex subsp. rex. (3) Timesequences prediction analysis showed a decreasing trend in the number of individuals in JM population after 2, 4 and 6 years of age class in the future. However, the XM populations showed an increasing trend after 2, 4 and 6 years. Therefore, we suggest that the protection and management of wild habitat of R. rex subsp. rex populations should be strengthen to maintain its natural regeneration.