The contributions of emission reduction and meteorological changes to air quality improvement in Hubei Province (HB) have required assessment in recent years. In this study, the WRF-Chem scenario tests were conducted to evaluate the effect of both the emission and meteorological changes on the winter PM_2.5 from 2015 to 2019, especially that of regional transport and local emissions on the PM_2.5 variations in HB. The results showed that meteorological changes in January 2019 increased the PM_2.5 by 24% relative to January 2015, whereas emissions reduced it by 36%, indicating that emission reduction was vital in improving the air quality in HB. However, the meteorological changes increased the concentration of air pollutants by 10–25% relative to January 2018. This led to a rebound of the observed pollutant concentrations in January 2019, highlighting the importance of meteorological conditions on air pollution. Regional transport of air pollutants contributed to the inter-annual increase of wintertime PM_2.5 by 78%, driven purely by meteorology from 2015 to 2019. This indicated that regional PM_2.5 transport could aggravate PM_2.5 levels in winter over HB with the reduction of air pollutant emissions in China. Additionally, the regional transport of air pollutants contributed to the decrease in PM_2.5 in HB by 42%, resulting from the non-local emission reduction during COVID-19 lockdown in winter. This indicates the importance of the regional transport of air pollutants in driving regional changes in the atmospheric environment over China.