Abstract: Sinojackia huangmeiensis J. W. Ge & X. H. Yao is one of 120 plant species with extremely small populations (PSESP) in China. In this study, independent-sample t test and Bayesian analysis of variance were used to compare the environmental conditions, fruit morphological traits, and fruit element contents of the only remaining ex situ conservation population and one wild population in Huangmei, China. Results showed that the wild and ex situ conservation populations were both located in subtropical areas, with similar mean annual temperature and precipitation. Fruit length, width, and length-width ratio were larger in the ex situ conservation population than in the wild population, whereas fruit mass showed similar trends without significant differences. Intraspecific variations in both fruit length and width of the ex situ conservation population were higher than that fruits of the wild population, and the variations in elements (except Ni) in soil and fruit were inconsistent between the two populations. Our results suggest that the ex situ conservation of S. huangmeiensis is generally successful, but populations are small.