<p>The research of modern and fossil soils was conducted at three archaeological sites: Nizhniy Kayancha, Novoilinka-3, and Tytkesken-2. Nizhniy Kayancha is a burial ground (dated 5th century BC) situated on the left bank of the Katun River (400-700 m above sea level). An archaeological site is a burial mound with seven mounds which can be visually separated within the site, and which are placed by small chains with 2–3 objects. The south mound of the first group was examined for a phytolith analysis. Еhe Novoilinka-3 settlement (dated 3rd millennium BC) is situated in the north of Kulunda, in the southern part of a hill formed by the false River Burla. The Tytkesken-2 settlement is situated on the verge of the stream Tytkesken, the left tributary of the Katun River, on its second terrace above the flood plain.</p><p>Geobotanical research was conducted in the territory of the archaeological sites under study. Grass phytoliths of modern flora were examined. Soil samples from different layers of the walls of excavation sites were collected. Phytolith extraction was based on the methods described by A.A. Golyeva. 20 g of soil, and 100 g of plant material of each species were processed during the initial period. The examination of the phytoliths of leaves, stalks and flower heads from the samples obtained from the plant material was carried out with the help of an optical microscope (Olympus BX-51). The phytoliths were counted to 250 (in ashed plants) and to 300 (in soils) particles.</p><p>More mesophytic plant communities of the ancient epochs have been reconstructed for all three examined archaeological sites. The territory of the Nizhniy Kayancha burial ground was covered by birch forest at the time prior to formation of the archaeological site. The territory of Novoilinka-3 settlement was covered by pine and birch steppificated forest in the Eneolithic period, but the territory was deforested as the settlement developed. Several stages of vegetation change have been reconstructed for the Tytkesken-2 archaeological site. This includes deforestation of pine forest and further steppe formation in the late Neolithic Age, prairiefication in the Eneolithic Age and new steppe formation in the Bronze Age up to the present time.</p>