Suaeda salsa is an annual euhalophyte. Fresh branches of S. salsa are valued as a vegetable, and the seeds contain edible oil. Seeds of S. salsa have a high germination rate under high salinity, but the soil NO₃^--N is very low in the habitat where the species occurs naturally. However, it is unknown how combined salinity and nitrate nitrogen during seed maturation affects the salt tolerance of seeds for this species. In the present study, we investigated the characteristics of ion accumulation and germination of seeds from plants cultured in different concentrations of nitrate nitrogen and salinity, in an attempt to understand the adaptation of S. salsa to high salinity and low nitrogen during seed maturation and germination. The results showed that S. salsa had a higher ability to maintain ion homeostasis (e.g., Na⁺, K⁺, Cl^- and NO₃^-) in embryos compared to pericarp or fruiting branches when plants were cultured at different concentrations of nitrogen and salinity (i.e., 0.5 and 5 mmol/L NO₃^--N combined with 1 and 500 mmol/L NaCl). Na⁺ and Cl^- concentration in the pericarp and fruiting branches were higher than those in embryos, especially at high NaCl (500 mmol/L) regardless of NO₃^--N concentration. At 500 mmol/L NaCl, the opposite trend was shown for K⁺ and NO₃^-. At 5 mmol/L NO₃^--N, the NO₃^-was higher in the pericarp, but lower in the fruiting branches than that in the embryos when plants was cultured in either 1 or 500 mmol/L NaCl, while the NO₃^-was lower in the pericarp and fruiting branches than that in the embryos at 0.5 mmol/L NO₃^--N supply. At 0.5 mmol/L NO₃^--N, the concentrations of Na⁺, K⁺ and Cl^- in embryos and pericarp were higher than those at 5 mmol/L NO₃^--N. The seed germination, germination index and vigor index were higher for seeds from plants cultured at lower nitrogen supply than seeds from plants cultured at higher nitrogen supply. In conclusion, the species may have a perfect ion regulation mechanism to maintain ion homeostasis during seed maturation. Compared to seeds from plants cultured in higher nitrogen supply, seeds from plants cultured in lower nitrogen supply had higher seed germination, germination index and vigor index, which may be related with higher concentrations of Na⁺, K⁺ and Cl^- in embryos and pericarp of seeds from plants cultured in lower nitrogen supply. The trait may be related to the adaptation of S. salsa to low soil NO₃^--N content in the habitat where the species occurs.