Abstract: This paper intends to find out the effects of plant growth regulators on flowering and the metabolism of hormones and polyamines during flowing of Dianthus chinensis L.Small pieces of young leaves of Dianthus chinensis L.collected from the campus of Nanjing Forestry University in spring were cultured on the dedifferentiation medium of MS+6BA 2.0 mg/L+2,4D 0.2 mg/L after sterilization.Green yellow calli were induced from the explants after one week of culture and then were subcultured on the differentiation medium of MS+KT 0.3 mg/L+6BA 0.3 mg/L+NAA 0.1 mg/L.Four weeks later,shoots appeared in some culture bottles.4～5 cm long shoots were cut at bottom and the same amount of shoots(60) were cultured on control MS medium and treat MS media supplemented with 6BA or NAA with serial concentration of 0.05 mg/L,0.2 mg/L,0.5 mg/L,1.0 mg/L.The experiments were repeated 4 times.Flower buds appeared on some media two weeks after inoculation and then flowered 4～5 days later.The apexes were collected every 5 days from the beginning day of culture for detecting the contents of zeatin tiboside group(ZRs),isopentenyl adenine group(iPAs) indole3acetic acid(IAA),gibberellin acid(GA1/3),abscisic acid(ABA),putresine(Put),spermidine(Spd),spermine(Spm) and diaminopropane(Dap).The culture results showed that 6BA inhibited flowering:0.1 mg/L 6BA decreased the flowering rate from 33.3% to 20% significantly and 0.5 mg/L 6BA inhibited flowering completely.0.1 mg/L and 0.2 mg/L NAA enhanced the flowering rate significantly to 56.7% and 71.7% respectively while 0.5 mg/L NAA decreased the flowering rate significantly to 21.7% and 1.0 mg/L NAA inhitited flowering entirely,which indicated that NAA promoted flowering with low concentration and inhibited flowering with high concentration.Endogenous iPAs,ZRs,IAA had their peak contents during flowering,and their higher contents were more favorable to flowering.But the development was affected by the ratio of IAA/(iPAs+ZRs),and when the ratio was low,D.chinensis L.remained vegetative growth.Among the PAs,Spd had the closest relationship with flowering.It reached a highest content during flowering and NAA with low concentration promoted the highest content.