The lacustrine and fluvial sediments in the Nihewan Basin from Late Pliocene to Late Pleistocene contain rich pollen and spore grains,which can be used to reconstruct past climate changes. Sediment samples are collected in the NHA borehole at Haojiatai,eastern part of the Nihewan Basin, Yangyuan County, Hebei Province. The drilling coordinates are 40°13'0.4"N,114038'32.3〃E and 938 m a.s.L The total sampling depth is 365.82 m. The samples were taken from the top of the Pliocene,19.2 m in thickness and 15600 ~17520 cm in depth. One sample was collected every 20 cm for the core of this section, and a total of 97 samples were obtained. In this study, Haojiatai NHA drilling core in the Nihewan Basin was selected to discuss the characteristics of vegetation and climate changes in Late Pliocene based on the pollen and grain size analysis of 97 samples. According to the existing paleomagnetic and stratigraphic contrast, the age of the sampling strata is from 2.92 Ma to 2.56 Ma. Based on pollen and grain size analysis, 4 stages with different climate and vegetation can be divided: Stage 1(2.92~2.82 Ma), the broad-leaved trees had the highest percentage in the full section with about 13%. Pinus pollen content was more than 30% and Picea were less than 20% in most samples and Artemisia and Chenopodiaceae were 10% ~20%. This indicates that broad-leaved forest and pine forest should be the main vegetation type in the sampling point, with some spruce forest existing in the mountainous regions,and that the climate was relatively warm and humid. Stage 2 (2.82 ~ 2.71 Ma),the pollen percentages of Picea, Artemisia and Chenopodiaceae increased significantly, with the maximum of 90% for Picea and 80% for Artemisia and Chenopodiaceae; on the contrary, the pollen percentages of Pinus and broad leaved trees significantly reduced to lower than 10% and 5% separately; which indicates that during this period,the surrounding vegetation became Picea forest or steppe and the climate tended to become chilly with severe fluctuation of humidity. Stage 3 (2.71 ~2.66 Ma), Pinus pollen percentages increased significantly,with more than 40% in most samples. The percentage of fern spore was about 11%,reaching the highest in the whole section; instead,Picea percentage decreased obviously,with less than 30% in most samples, and broad-leaved trees pollen was rare and the percentage of Artemisia and Chenopodiaceae was less than 10%, indicating that the surrounding vegetation was dominated by pine forests, and the spruce forest retreated to the mountainous regions, and the climate became relatively warm and wet, but the rareness of broad-leaved pollen indicates that the degree of warmth is lower than that in Stage 1. Stage 4(2.66 ~2.56 Ma),Picea became the dominated pollen type with more than 80% percentage in most samples, and Pinus was reduced to less than 10% and broad-leaved forest pollen grains were rarely be recorded suggesting that Picea forest expanded to the nearby of sampling site and the climate was getting much colder and connected to the Pleistocene glacial period. According to the pollen analysis, there are two relative warm periods (2.92 ~2.82 Ma and 2.71 ~2.66 Ma) and two cold periods in the Late Pliocene (2.82 ~2.71 Ma and 2.66 ~2.56 Ma) respectively. The stages with high Picea pollen percentage, had good correspondence with the deep-sea oxygen isotopes periods of MIS 102,MIS 104,G2,G6 and G10,which represents the cold climate.