Abstract: In this study, wild type（WT） and GhPAO3 transgenic Arabidopsis seeds were used as materials to study the effects of NaCl and exogenous polyamines and polyamine inhibitors on germination of WT and transgenic Arabidopsis seeds. Different concentrations of NaCl treatment showed that the inhibition of Arabidopsis seed germination was more obvious, with the increase of NaCl concentration. 150 and 200 mmol/L NaCl treatment delayed seed germination for 1 and 2 days, respectively, and the germination rate of transgenic Arabidopsis was lower than that of WT, indicating that the overexpression of GhPAO3 gene may inhibit the germination of Arabidopsis thaliana seeds under NaCl treatment. In addition, under the condition of 100 mmol/L NaCl treatment, the cotyledons of WT turned green on the 3 rd day, while the cotyledons of transgenic plants turned green on the 4 th day, and the number of cotyledons of transgenic Arabidopsis turning green was lower than that of WT,and it was speculated that the H₂O₂ produced from NaCl treatments and over expression lines could inhibit the Arabidopsis leaves turning green.Exogenous polyamine and polyamine inhibitor treatment showed that exogenous polyamine and PAO inhibitor（1,8-DO） could promote cotyledon greening, and H₂O₂ content in transgenic lines was higher than that of WT. In the case of polyamine inhibitor（D-Arg）, the content of H₂O₂ in the transgenic strain was lower than that of WT. This study revealed the effect of GhPAO3 gene on seed germination, and provided reference for further understanding the role of polyamine oxidase in plant growth and development.