During the whole geological time the change of paleobioclimatic factors of environment under the influence of climate represents considerable inter-est. Paleosols are capable of keeping important diagnostic criteria promoting carrying out recon-struction of environment during the last geological periods. Inundated paleosols are an example of well remained paleosols as a result of catastrophic nature of these processes. The morphological and micromorphological characteristic of humic hori-zons inundated paleosols, their analytical indica-tors, floro-faunistic data allowed to diagnose eco-logical conditions of their formations. In the Holo-cene during its different climatic periods the change of natural complexes from forest to steppe land-scapes was observed. During the warmest and dry periods of the Holocene in the floodplain of the Ye- nisei River chernozyom and meadow and chernozyom soils were formed. Their safety was connected with high stability of colloidal part under the influence of the subsequent natural processes. The most accurate criteria of diagnostics of paleosols were used: morphological and micromorphological structure, particle size distribu-tion, carbonate contents, humic and fractional structure of humus. At reconstruction of inundated ecosystems complexity of structure of ecosystem, namely paleosols type, the remains of flora and fauna and feature of climatic changes was consid-ered. The feature of manifestation of soil formation processes, the condition of vegetable communities and the structure of soil fauna occupying this terri-tory were defined by the main factor - climate. As an optimum phase of the Holocene for Central Ye-nisei it is possible to consider the Atlantic period of the Holocene (its first half). At this particular time the optimum ratio of heat and moisture leading to the increase in biodiversity was observed.