Myricaria wardii is one of species of Myricaria,which is endemic to Tibet and an important resource of Tibetan medicine. It is mainly distributed in the basin of three branches of Yarlung Zangbo River (or Yarlung River, for short), namely Niyang River, Lhasa River and Nianchu River. In order to explore the population structure and distribution characteristics of M.wardii species, 15 sample plots and 5 sample sites in each plot, were determined, and from which we collected basic diameter of M.wardii. Population dynamics quantization and time sequence analysis were used to predict potential population changes of M.wardii. Characteristics of the population structure were described by establishing a static life table and drawing a population survival curve. The results showed that the population diameter class structure of M.wardii species in the basin of three branches of Yarlung River was atypical pyramid structure with narrow bottom and enlarged middle. The dynamic index showed that the population of M.wardii. in the three tributaries were all growing, but the growth was not obvious, and they were sensitive to external disturbances and had poor anti-interference ability. The static life table and the correlation curve showed that the survival number and life expectancy of the populations of M.wardii in the three tributaries gradually decreased with the increase of diameter class. The populations of M.wardii in the three tributaries all fluctuated to varying degrees, showing an unstable state as a whole. Both survival analysis and time series analysis showed that the lack of seedlings was the main reason for the decline of M.wardii in the future, and it was predicted that the populations of M.wardii in the Nianchu River and Lhasa River would enter the decline period sooner, while the decline period of the populations of M.wardii in the Niyang River were relatively later. At the same time, the proportion of seedlings was significantly positively correlated with the precipitation where the population was in, so that the Niyang River Basin with high precipitation was more suitable for the survival of M.wardii. However, the population of Myricaria wardii is more sensitive to disturbance in this environment. It is recommended to strengthen the protection of the seedlings of M.wardii population while developing economy of the three tributaries of the Yarlung River, then protect and improve the population environment of M.wardii, so as to maintain its natural renewal and recovery.