Abstract: The classic chrysanthemum ‘Mona Lisa sunny’was used as material,the effects of B9 and PP333 on the ornamental characters and physiological indexes of chrysanthemum were studied by foliar spraying,in order to obtain the optimal dwarfing conditions and achieve the best pot culture effect.The results showed that both B9 and PP333 made the chrysanthemum dwarf effect,increased the branches,and the effect of PP333 was greater than that of B9.At the same time,both of them sped up the process of bud differentiation,which showed that they made chrysanthemum blossom earlier and prolong the flowering period（ornamental period）.Both B9 and PP333 increased the content of chlorophyll and soluble sugar in late reproductive growth stage,while both B9 and PP333 reduced the endogenous hormones gibberellin and auxin in the same growth stage.Comprehensive analysis of two plant growth retardants in different concentrations on chrysanthemum ‘Mona Lisa Sunny’led the result that PP333 with concentration of 400 mg·L^-1 was the best option under this treatment which had many advantages,such as moderated plant height,compacted plant type,not proned to lodging,thick green leaf color,extended florescence,etc.,which improved the ornamental value of potted chrysanthemum.