Abstract: The aim was to understand phenotype plasticity and regulations of reproductive modules on Polygala fallax Hemsl. population. By large sampling analysis, the phenotype plasticity of reproductive modules on Polygala fallax Hemsl. population was studied. The results showed that the biomass of each reproductive ramet of Polygala fallax Hemsl. population was (58.67±35.77) g; the biomass and number of pods were respectively (6.64±4.93) g and 35.6±30.50; the biomass and number of seeds were respectively (2.61±2.19) g and (61.97±54.15); reproductive allocationⅠ(RAⅠ) and reproductive allocationⅡ(RAⅡ) were respectively 10.55%±3.39% and 3.93%±1.62%; the maximum in the observed phenotype date of reproductive module were 4.23- 39.5 times more than the minimum. There were most significant positive correlations between the biomass and number of pods and seeds and the total biomass of ramets, respectively (P＜0.01), which could be described by linear equations. There were most significant negative correlations between the number of pods and seeds, RAⅠ, RAⅡ, and the allocations of component, respectively (P＜0.01), which could be described by power function. There were two different regulations of phenotype plasticity in productive plants of Polygala fallax Hemsl. population at the time, which were processes of increase/decrease for the isogeny and allometry.