Our aim is to investigate biseasonal flowering phenology and reproductive features of Tamarix ramosissima. The study was conducted in wilderness region of Mosuowan which is located at the southern edge of Gurbantunggut Desert. We observed the flowering phenology index, flower characteristics changes of the flowering course and fruit set characteristics in the wild population of T. ramosissima. The results showed that: (1) the spring flowering period of T. ramosissima. was from the late May to early June, exhibiting a “massflowering” pattern. The summer flowering period was from the middle June to early September, exhibiting an “extendedflowering” pattern. (2) In the spring flowering period and the summer flowering period, the flowering duration of the population, individuals, inflorescences and single flower were 14, 10, 3, and 1 d, and 85, 77, 2, and 1 d, respectively. (3) There were significant correlation among first flowering date, flowering duration, flower number and fruit number at inflorescences of the summer flowering period. (4) There was no significant differences in the flowering process and morphological structure between two flowering periods. (5) The fruit rate and seed rate in spring flowering period are same higher than that in the summer flowering period, but there was no significant difference between two flowering periods. (6) Pollination times in spring flowering period is significantly higher than that in summer flowering period. (7) There was no significant differences in the pollen vitality between two flowering periods, the stigma receptivity in spring flowering period is longer than that in summer flowering period. The survival conditions in wilderness region of Mosuowan is poor, biseasonal flowering phenology and reproductive features of T. ramosissima raise the possibility of their reproductive success.