Abstract: The regulatory effects of salinity,pH and temperature on NH₄⁺ dynamics in tidal flat sediments were investigated along the Yangtze delta,using sediment slurries.It was shown that when salinity and temperature were increased,all curves of NH₄⁺ released from sediments increased with similar trends.However,the effects of pH on NH₄⁺ released from sediments were unclear.In addition,the type of sediment affected the magnitude of release of NH₄⁺,resulted in the fact that its magnitude was always lower in the low flat with high-content sands than that in the high and middle flats with low-content sands.