Abstract: In order to explore the effects of different concentrations of Paclobutrazol and bupizide on the dwarfing of potted dahlia, the potted rose red two-color dahlia was used as experimental materials, and the growth retardants bupizide and Paclobutrazol were regularly and quantitatively sprayed on dahlia seedlings to investigate the effects of two growth retardants on the plant type and chlorophyll content of potted dahlia.The results showed that butyryl hydrazide and Paclobutrazol had different effects on plant height, crown width, leaf length, leaf width and chlorophyll content of rose red two-color dahlia.Under 150 mg·L^-1 Paclobutrazol treatment, the plant was dwarfed, the leaf shape was not affected, the leaf color was deepened, the leaf was thickened, the plant resistance was strengthened, the plant shape was compact and full, and the ornamental effect was good.The 2 500 mg·L^-1 butyryl hydrazine treatment had the best effect of dwarfing plants, compact plant type, thick green leaves and strengthening stress resistance.On the whole, butyryl hydrazide has a better dwarfing effect on rose red two-color dahlia than Paclobutrazol, which is more suitable as a treatment agent for dwarf cultivation of rose red dahlia.