The authors introduced the results of studying the deposits of peatland "Kuskun" in the floodplain of the Esaulovka River (Kansk forest- steppe). Peatlands are an important natural archive for past climatic changes, primarily due to their sensitivity to changes in the water balance and the dating possibilities of peat sediments. Climatic changes throughout the Holocene have been reconstructed from peat, using a wide array of biological and other proxies. Many different proxy-indicators can be derived from peat cores. Peat-based climatic and environmental reconstructions are currently available from many sites in Yenisei Siberia, mainly for its northern territories. The purpose of this research is to study some features of peatland's development and environmental reconstructions from the Holocene period in the south part of Yenisei Siberia (Kansk forest-steppe zone).The main method of the research is macrofossils analysis of peat. The analyses of plant macrofossils can be used to reconstruct the development of the local vegetation and surface wetness on peatlands, and thus to elucidate successional processes. To interpret these proxies by macrofossils analysis, the current botanical composition of the bog and the ecological behavior of different plant species were used. The analysis of plant macrofossils in the peat, based on the study of the flora and vegetation in a particular place over a period of time, has allowed the reconstruction of environmental changes that have occurred since the Late Glacial. Macrofossil types were identified with Kac and Kac Atlas. The reconstruction of the bog surface wetness was performed on the basis of the analysis of plant macrofossils. After that, we used the ecological scales of moisture and reconstructed surface wetness for the entire period of the peatland formation. Radiocarbon dating was carried out at Sobolev Institute of Geology and Mineralogy, Russian Academy of Sciences, Novosibirsk .We assessed humidity conditions during the whole period of peat accumulation and marked different phases in the development of peatland,we described their vegetation. We concluded that peatlands in Esaulovka River basin formed about 5000 years ago. It was found that all peatbogs are at the eutrophical phase. The peatlands formed as a result of overgrown oxbow lakes, floodplains and water logging of terrace lows. This research allowed determining the age of the peat deposits and the average rate of peat accumulation was 0.45 mm/ year.