Abstract: Phenotypic traits of the natural Gaura parviflora population represent its adaptation to natural environments. Comparison of phenotypic traits among different populations can provide important clues for understanding phenotypic variation and formation processes of G. parviflora. We investigated 16 phenotypic traits in 5 G. parviflora populations located in the coal-gangue pile of Yima and compared variations in phenotypic traits in natural conditions. Our results showed that the average variation coefficient of phenotype traits was 36.30%, which indicated the comparatively abundant phenotypic diversity in G. parviflora. The phenotypic differentiation coefficients (V_st) ranged from 26.85% to 96.98%, the mean value was 73.03%, which indicated that the variance among populations was the main part of the phenotypic variation. Different traits responded differently to environmental changes. Plant height, base stem diameter, number of fruit per plant and specific leaf area were similar among individuals within a populations, but differed from each other significantly among populations. The phenotypic differentiation coefficients (V_st) of them were more than 82%. There were significant differences in the phenotypic traits of internodal space, leaf width, root length, branch number, fruit length and fruit width among populations and among individuals within a population. Number of seeds per fruit and single fruit weight were similar among populations and among individuals within a populations. Plant height, base stem diameter, leaf length, leaf width, stem biomass, leave biomass, root biomass and number of fruit per plant showed a consistent integration pattern, which helped to increase the ecological adaptation of G. parviflora. Cluster analysis showed that different populations from the similar habitat conditions grouped together, further showing that the phenotypic traits of G. parviflora were strongly influenced by the habitat factors. The correlation analysis showed that the majority of phenotypic traits significantly correlated with habitat factors, while the fruit traits (fruit width, single fruit weight and number of seed per fruit) did not, which indicated that reproductive traits were not influenced by the environmental factors.