Abstract: This study aimed to understand the difference of assimilation ability oftwo cut flower Chrysanthemum, and to compare the ability of different leaf positions to adapt to low light, in order to provide theoretical basis for production management of facility cultivation. ‘Jingba’ and ‘Youxiang’ were measured by GFS-3000 portable photosynthetic system to understand their photosyntheticcharacters and light response curves were fitted. [Result] The results showed that the photosynthetic parameters, e.g. the average of net photosynthetic rate (Pn), transpiration rate(Tr), intercellular CO2 mole fraction(Ci) and stomatal conductance(Gs)of ‘Jingba’ were a little higher than that of ‘Youxiang’ except water use efficiency (WUE); but the leaves of Pn and WUE of different positions of ‘Youxiang’ differed greatly, which those of the upper leaves were 3.51μmolm-2s-1and 2.47 mmolm-2s-1 and were 6.26 times and 8.23 times of the lower leaves, respectively. This suggested that the photosynthetic capacity and water use efficiency of ‘Youxiang’ decreased significantly with the increase of the ages. According to the maximum net photosynthetic rate (Pmax) and light saturation point (LSP), the modified rectangular hyperbolafittedthe light response curve of cut flower Chrysanthemum well. The variation tendency of Pmax, apparent quantum efficiency (AQE) and LSP of 2 cultivars were consistent, from top to bottomof the leaf position it was gradually decreased. While the Pmax of different leaf positions of ‘Youxiang’ varied remarkably, the same as that of Pn. But the LSP and AQE of ‘Jingba’ was higher, so it had a wideradaptation to light intensity and was more suitable for sunlight greenhouse cultivation.