Distylous plant is a special group of angiosperm which has reciprocal stigma and anthers within a species. Comparative investigations of breeding system of distylous species on different elevations can be revealing the relationship between distylous plant evolution and their environments. Primula nivalis is a native primrose in the northern Xinjiang, NW China. In order to investigate the comparative effect of habitat heterogeneity on frequency of morphs in different sexual morph plants and differentiation of floral characters were quantified at seven lowelevation forest (1 657-2 013 m) and seven highelevation grassland populations in this research. The study results will clarify the reproductive strategies and adaptation mechanisms of P. nivalis at different elevational environments. (1) The investigations on effect of heterogeneous habitats on P. nivalis floral phenotype suggested that frequency of LS (long style) morph individuals in high elevation grassland population was higher than that of SS (short style) morph individuals; (2) The floral morphological characters of LS among populations in different ecological conditions were significant different, but no significant difference for SS morphs with different ecological conditions; (3) The length of corolla tube and stamen, and stamenstigma spatial distance, herkogemy and relative reciprocity of LS flowers in high elevation grassland population are the main factors for floral trait differentiation in P. nivalis at heterogeneous environments; (4) This revealed that variation of LS floral characters at different population decreased the herkogamy level of both morph flower sexual organs in high elevation grassland populations. Therefore, changes of floral trait of LS plants are the main factors for floral trait differentiation and relative reciprocity of both morph flowers in heterogeneous environments.