The dredging of rivers and lakes in China produces a large amount of waste silt every year，which has long consolidation period，low curing strength and heavy metals，and is difficult to be used as resources.In this paper，ultrafine metakaolin geopolymer is used to study its influence on the solidification strength，water stability coefficient and heavy metal consolidation effect of the silt.The results show that with the increase of ultrafine geopolymer content，the strength of silt solidified soil gradually increases，and the 7 d unconfined compressive strength can reach 1.68 MPa，which has excellent silt solidifying effect.The water stability coefficient increases first and then decreases，and the water stability coefficient of the silt solidified soil mixed with ultrafine metakaolin is more than 90%，which is more than twice that of the pure silt soil.The ultrafine geopolymer has good consolidation effect on 6 kinds of heavy metal ions such as cadmium and lead，especially on cadmium and mercury，and the leaching amount of 6 heavy metal elements in each group of silt solidified soil does not exceed the requirements of relevant standards.The solidification and heavy metal consolidation effect of the ultrafine geopolymer on the silt is good，which is quite different from the ordinary Portland cement solidifying material.