The long-term evolution of vegetation and hydroclimate since the Late Miocene, along with its driving mechanisms, remains debated. This is partly because of the lack of a comprehensive set of terrestrial vegetation and climate records spanning key geological periods with robust chronological framework. Here, we present a long time-scale pollen records from a drilling core in the North China Plain to reveal the evolution of vegetation, and to quantitatively reconstruct paleoprecipitation. The magnetostratigraphic results indicate that the sedimentary sequence was deposited since similar to 6.5 Ma. The pollen assemblages and quantitative reconstructions of paleoprecipitation indicate a vegetation transition from grassland to forest at similar to 4.9 Ma, accompanied by an increase in mean annual precipitation from similar to 464.7 to similar to 563.4 mm, followed by a reversion to grassland at similar to 1.7 Ma, with mean annual precipitation decreasing to similar to 334.2 mm. A comparative analysis of herbaceous pollen percentages and paleoprecipitation proxies demonstrates that these phased dry-wet climate variations have been widespread across northern China since similar to 6.5 Ma. While atmospheric CO2 concentration was the dominant control, mountain uplift played a significant role during similar to 3.4-1.7 Ma. This study suggests that elevated greenhouse gas concentrations can induce prolonged humid conditions in northern China. Our findings enhance the understanding of vegetation-hydroclimate feedback mechanisms under global warming and provide critical boundary constraints for palaeoclimate modelling in East Asia.