The topsoil with different nitrogen (N) treatments (NS0, NS1, NS2 and NS3) were sampled at the end of the growing season from the corresponding N import plots (N0, no N import treatment; N1, low N import treatment; N2, middle N import treatment; and N3, high N import treatment) in Suaeda salsa marsh in high tidal flat of the northern Yellow River estuary and their sulfur (S) mineralization were investigated by means of an open-incubation system at 25 ℃ at un-flooded and flooded conditions. The results showed that, the mineralized S in soils with different N enrichments at un-flooded condition showed NS3 > NS1 > NS2 > NS0, while those at flooded condition demonstrated a similar tendency, and for each treatment, the value of sulfur mineralization reached the maximum all at the third day of incubation. And in different incubation conditions, the variations of sulfur mineralized in soils with different N enrichments might be related to the variations of pH and EC during incubation. During 119 d incubation, the cumulative amounts of mineralized S in NS0, NS1, NS2 and NS3 were 233.03 mg/kg, 419.99 mg/kg, 401.16 mg/kg, and 526.51 mg/kg at un-flooded condition and 263.52 mg/kg, 313.58 mg/kg, 251.53 mg/kg and 322.05 mg/kg at flooded condition. The cumulative amounts of mineralized S in soils with different N treatments were mainly dependent on the mineralization contributions of initial stage (0-14 d), and the values at un-flooded and flooded conditions were 41.01%-54.53% and 79.49%-86.82%, respectively. Except for NS0, the higher cumulative amounts of mineralized S were observed in NS1, NS2 and NS3 at un-flooded condition compared to those at flooded condition, indicating that higher potential of mineralized S generally occurred at un-flooded condition. Both the cumulative amounts of mineralized S and the potentially mineralizable S (S₀) in soils at un-flooded condition showed NS3>NS1≈NS2>NS0, whereas those at the flooded condition showed NS3≈NS1 > NS0 > NS2, indicating that the highest potential of mineralized S in soils occurred in high N enrichment (N3). The study found that, in future, increasing of N loading in the Yellow River estuary would promote the mineralization of S in soils by altering their substrate qualities, which, to some extent, enhance the potentially supply capacity for S. However, as the marsh soil was flooded at short-term period due to the influence of severe precipitation, spring tide or storm surge, the potentially mineralizable S in marsh soil would decline significantly and, particularly, the decrease amplitude was evident in middle N enrichment (N2).