Abstract: The two peat sections are situated in the Xiaowangzhung, Yanqing County and Xinglitum, Haidian district, respectively.Many pollen grains of arboreous, shrubs and herbaceous plants are found in the peat sediments. They belong to the genera Pinus, Querous, Betula, Ulmus, Tilia, Ephedra, Artemmisia etc. and families Chenopodiaceae Gramineae Cyperaceae Compo-sitae etc.Three vegetation phases from the lower to upper parts of the sections may be distinguished by the pollen analysis. The lower part of the sections represents a coniferous forest phase, mainly consisting of Pinus or the coniferous-broad forest phase of Pinus and Betula, while the middle and upper parts represent the coniferous-broad forest phase, mainly consisting of Pinus, Querous, Betula, Ulmus and Tilia and coniferous forest phase of Pinus, respectvely.The results of pollen analysis show that the climate was changing during the formation of the peats. In the early stage the prevailing climate was warmer and drier, in the middle stage was the warm and moist climate and in the late stage was the cooler and drier climate dominated.Based on the polynological date C¹⁴ age deteminalion, the geological ages of two peat ore sections are described as the Early Holocene for the lower part, the Middle and Upper Holocene for the middle and upper parts respectively.