Effect of exogenous spermidine(Spd)on growth and chlorophyll precursors content of spinach plants under NaCl stress was studied by hydroponics using ‘cv.Quanneng’ of spinach,a sensitive cultivar to salt.The results showed that:(1)growth of spinach plants was inhibited significantly by 250 mmol·L^-1 NaCl,as a result of total fresh weight,total dry weigh,shoot fresh weight,shoot dry weigh,root fresh weight and root dry weigh of spinach plants were significantly decreased by 57.23%,53.08%,63.14%,55.05%,42.22% and 42.86%,respectively,as compared with control.However,plant growth was enhanced by 1.0 mmol·L^-1 Spd,those indexes increased by 62.83%,71.19%,60.57%,71.74%,70.31% and 69.23%,respectively,as compared with salt stress treatment.(2)Chlorophyll a(Chl a),chlorophyll b(Chl b)and total chlorophyll[Chl(a+b)] contents in leaves of spinach plants were decreased by 250 mmol·L^-1 salt stress to 42.31%,54.55% and 44.53%,respectively,but those were increased by 1.0 mmol·L^-1 Spd to 46.24%,51.85% and 47.11%,as compared with salt stress treatment.(3)Chlorophyll precursors such as Chl a,Chl b,protochlorophyll(Pchl),Mgprotoporphyrin Ⅸ(Mgproto Ⅸ),protoporphyrin Ⅸ(Proto Ⅸ)and uroorphyrinogen Ⅲ(Uro Ⅲ)were decreased by salt stress,but were increased by Spd.However,others such as δaminolevulinic acid(ALA)and porphobilinogen(PBG)were enhanced by salt stress,but were suppressed by Spd.These results suggested that chlorophyll synthesis process from PBG to Uro Ⅲ was inhibited by salt stress,and this inhibition was alleviated by exogenous Spd,as a result of chlorophyll increasing.