Cinnamomun micranthum is a rare cash plant of Cinnamomun which occurs in mainland and Taiwan Province, China. It was listed as a Grade Three endangered plant for State protection in 1982 as its abundance was decreasing rapidly. The surviving Cinnamomun micranthum commonly has very low reproduction and natural regeneration ability. Although some studies have been recently conducted of the phenology, sexual reproduction and asexual reproduction of Cinnamomun micranthum, there has been no research into its population dynamics. In order to determine the population state of Cinnamomun micranthum, analyze its past population structure and pre-disturbance situation and forecast its future population dynamics, the population life table and periodic fluctuation of Cinnamomun micranthum were analyzed by the space deducing time method. The static state life table, the survival rate curve, the mortality rate curve and danger rate were compiled using the diameter at breast height class to represent the age class structure and smooth out technique. The results showed that the survival curve of the population appeared to be of the Deevey-Ⅲ type. According to the mortality rate curve, the mortality peaks of Cinnamomun micranthum are in the first and fourteenth age grades. The high mortality of seedlings and middle-age trees was one of the main reasons which led the Cinnamomun micranthum population becoming endangered. The natural regeneration process of the Cinnamomun micranthum population can be represented by the fluctuation of the distribution of the number of trees in different age grades. Spectral analysis of the population showed that the natural regeneration of Cinnamomun micranthum was a minor periodic change in eleventh and fifteenth age grades.