Abstract: The impacts of salt stress on the growth index, chlorophyll content, photosynthesis and chlorophyll fluorescence parameters of Gossypium barbadense seedlings were studied for providing theoretical evidence on materials breeding, cultivation of salt stress. Two Gossypium barbadense strains, Yuehai 9 (salt tolerance) and PS-7 (salt sensitive) were selected, and germinated in full nutrient solution. 150mM of NaCl was added into solution from germination stage to 3-leaf stage. The response of Gossypium barbadense seedlings to NaCl stress was assessed by measuring the growth index, chlorophyll content, photosynthesis and chlorophyll fluorescence parameters. The results showed that, under continual NaCl stress, the leaf area, root length, stem length, root/stem ratio, chlorophyll a, chlorophyll b, total chlorophyll content were reduced and chlorophyll a/b ratio was enhanced in the Yuehai 9 and PS-7. Salt stress increased net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), water use efficiency (WUE), actual photochemical efficiency of PSⅡ (Y(Ⅱ)), photochemical quenching (qP), relative photosynthetic electron transport rate (rETR), and decreased maximal quantum yield of PSⅡ (Fv/Fm), non-photochemical quenching (NPQ) in the Yuehai 9. Salt stress reduced net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), water use efficiency (WUE), maximal quantum yield of PSⅡ(Fv/Fm), actual photochemical efficiency of PSⅡ(Y(Ⅱ)), photochemical quenching (qP), relative photosynthetic electron transport rate (rETR), and enhanced intercellular CO2 concentration (Ci), non-photochemical quenching (NPQ) in the PS-7.The root/stem ratio in the PS-7 was greater than this in the Yuehai 9, the other indexes in the PS-7 were less than that in the Yuehai 9. Continuing NaCl stress exerted an obviously adverse effect on Gossypium barbadense seedlings growth and biomass accumulation. The strong salt tolerance strain were more tolerant to salt stress than the salt sensitive strain. Under salt stress, the decline of net photosynthetic rate in the PS-7 was restricted by non-stomatal factors, the major reason on the increase of net photosynthetic rate in the Yuehai 9 was the advance of actual photochemical efficiency of PSⅡ. The growth index, chlorophyll content, photosynthesis and chlorophyll fluorescence parameters can be used as reference indexes on the identification of the salt tolerance of the material.