The Effects of waterlogging on root vigor, chlorophyll content, photosynthetic characteristics and morphological changes in five related species of Dendranthema were studied. The waterlogging was mimicked by treating pot plants with flooding (2-3 cm in depth). Waterlogging tolerance of five species was evaluated. The results showed that the root vigor of five species all declined significantly under waterlogging, except that Dendranthema zawadskii showed high root vigor in the early stage of waterlogging stress.The chlorophyll contents of the five species increased during the early stages of stress and then decreased afterwards；After flooding treatment for 15d, in Ajania shiwogiku Kitam. var. kinokuniense and Dendranthema boreale, the net photosynthetic rate declined significantly, CO2 assimilation declined as well and even decreased to negative value which suggests that photosynthetic capacity was lost. Obvious decrease in photosynthetic rate was also observed in Dendranthema crassum and Dendranthema yoshinaganthum. However, Dendranthema zawadskii maintained higher net photosynthetic rate under the stress. The leaf morphological changes under the waterlogging suggested that Dendranthema zawadskii is most tolerant species, whereas Dendranthema boreale is the most sensitive species, Dendranthema crassum, Ajania shiwogiku Kitam. var. kinokuniense and Dendranthema yoshinaganthum showed moderate tolerant to waterlogging stress.