Abstract:The authors examined the dynamic features of flavonoids and Gynostomma. saponin in the different Gynostemma pentaphyllum populations under natural conditions and their ecological significance through the plant physio- ecological methods. The results show: (l) the dynamic patterns of flavonoids and G. saponin in the stems, blades and shoots in the populations under the same surroundings are different. At different phases of life history of the populations , the stems and blades have different effects on flavonoids and G. saponin in the popu-lations; (2) the dynamic patterns of the two kinds of substances vary with different populations; (3) flavonoids and G. saponin have their own physiological functions, moreover, they have both plasticity; (4) the dominant environmental factors affecting the dynamics of flavonoids and G. saponin are different. Thus secondary metabolic products play a very important role in the life history of plant populations.