Seedlings of Salicornia bigelovii Torr.were treated with different concentrations of NaCl (0,100,200,300,400,500 mmol·L^-1).Three kind of polyamines and their different forms were investigated under NaCl and exogenous spermidine treatment.The results showed that:（1）three forms of the putrescine (Put) increased at first and then decreased under salt treatment.The free form of spermidine (Spd) and the bound state of spermine (Spm) increased all the time.The free form of Spd,the conjugated state of Spd and Spm,and the bound state of Spd both increased at first and then decreased.Finally,the total polyamines (PAs) of the free and bound were both increased all the time,while the conjugated state content increased at first and then decreased.（2）All the three forms of polyamines of (Spd+Spm)/Put ratio increased at first and then decreased,while the Put/PAs ratio was decreased first and then increased.（3）The conjugated and bound form of the polyamines contents increased with exogenous Spd treatment.At the same time,the free and bound states of (Spd+Spm)/Put ratio also increased.It indicated that exogenous Spd could be involved in the regulation of PAs metabolism and played an important role in enhancing salt tolerance of S.bigelovii seedlings.