Wind erosion is a major contributor to land degradation, and its accurate assessment relies critically on the erodibility factor. Yet, the erodibility factor widely used in dust models is quite uncertain. In this study, we developed an improved erodibility factor and incorporated it into the Integrated Wind Erosion Model System (IWEMS) and the Dust Entrainment and Deposition (DEAD) model to simulate wind erosion and dust emissions across China from 2000 to 2023. Validation against field measurements of sand and dust flux showed that the improved erodibility factor substantially enhanced model performance. Specifically, the Root Mean Square Error (RMSE) of sand flux decreased from 4.33 kg/m/d to 0.92 kg/m/d, and the Relative error (Re) decreased from 74.56% to 1.54%, while lowering the RMSE of dust flux from 1.04 g/m2/d to 0.75 g/m2/d and its Re from 18.03% to 1.67%. Long-term results reveal pronounced spatial heterogeneity and seasonal differences. Sand and dust emissions peak in spring and are lowest in summer. Spatially, the highest emissions consistently occur in major deserts, gobi regions, and sandy lands, with additional high-emission zones on the Qinghai-Tibetan Plateau. Scenario comparisons further illustrate that land-use changes since 2000 have reduced potential erodible surfaces and consequently lowered dust emissions in Northern China. Overall, this study provides a refined erodibility framework for long-term wind erosion assessment and offers quantitative evidence on how land-surface characteristics influence sediment availability at regional scales. The improved erodibility factor can serve as a fundamental dataset for future soil erosion modeling and land-degradation evaluations.