Iron plaque is commonly formed on the root surface of hydrophytes, and the formation of iron plaque is an important mechanism for the hydrophytes to adapt to the waterlogged sediments. Studies showed that iron plaque plays an important role in element uptake by plants. This paper summarized the formation of iron plaque, the composition, distribution and the amount of iron plaque on root surfaces. The influence of iron plaque on element uptake and its affecting factors were also discussed. The presence of iron plaque has been reported to inhibit the uptake of heavy metals by plants. On the other hand, iron plaque can act as a reservoir increasing the uptake of elements by plants during periods of diminished supply, or enhancing/reducing metal (loid) uptake by plants depending on the amount of iron plaque present on the root surfaces. The controversial results from different experimental results can be related to plants, metals studied and the techniques used in the experiments. Factors such as plant species, plant age, plant nutritional status, cultivation of the plants, ionic species and concentration in the growth medium, techniques for analyzing iron plaque etc can affect the experimental results. Future research should take account the environmental factors and integrate iron plaque in the frame of soil–plant continuum. Some in situ techniques should be employed to elucidate the nature of iron plaque and the chemical behavior of the elements in the iron plaque and plant roots.