Abstract:Tetraena mongolica is an endemic and endangered species，and is one of the Chinese national second protective wild plants being listed in the Red Data book. T. mongolica is distributed mainly in Western Ordos Plateau of Inner Mongolia. But for some reasons，the range of the population has been declining. This research was carried out in the natural distribution region and the different habitats of T. mongolica population in order to describe the structure and distribution pattern of the population. 7 plots were established and the field data were collected. Through drawing the charts of diameter-class，age-class，width-class，height-class in different habitats，the comparative analyzing was carried out. The dynamic of age structure of T. mongolica population was concluded according to the static life table, and the population distribution pattern indexes were calculated by using the method of Clark-Evans. The results showed：(1）The structures of diameter-class，age-class and height-class of T. mongolica population were in normal-distribution type. The structure of width-class showed approximate exponential decay. The population structure difference among the different habitats was definitely due to the different micro environments. (2）With the increase of population age-class，the survival rate was decreasing，and the mortality and vanish rate were increasing. The survival curve fitted the Deevey Ⅰwhich indicated the population was the descending-type. (3）The individual distribution of T. mongolica populations in different habitats were not even，and the spatial distribution pattern showed in random.