Abstract: In recent years, air pollutants emissions in China have reduced significantly, and thus led to improvement in air quality. However, annual mean PM_2.5 concentrations in some key regions such as the “2%2B26” Cities in Jing-Jin-Ji and surrounding areas are still relatively high, far exceeding the national standard II for ambient air quality.35 μg/m³. In this regard, Greenhouse Gas and Air Pollution Interactions and Synergies model adapted to the “2 %2B 26” Cities (GAINS-JJJ) model was applied to simulate and predict regional air quality under different policy scenarios in 2030, and contributions of structural adjustments and end-of-pipe controls (BAT) policies to the emission reduction. Results showed that (1) Due to the structural adjustment policies, such as ‘coal to clean energy’, elimination of outdated production capacity (such as steel, cement, coking, etc.), reduction of nitrogen fertilizer application and substitution of high volatile organic solvents, and the end-of-pipe control policies, such as ultra-low emission standard transformation of steel, cement and coking industries, strengthened emission standards of heavy diesel vehicles and non-road machinery, and promotion of standardized large-scale breeding, soil testing technologies, the average annual concentration of PM_2.5 in the “2%2B26” Cities reached 34 μg/m³, achieving the goal of “beautiful China”. (2) The emissions of PM_2.5, SO₂, NO_x, NH₃ and NMVOCs in 2030 will be reduced by 31%, 44%, 31%, 5% and 11%, respectively, compared to 2017, due to structural adjustments; and they are further reduced by75%, 69%, 77%, 32% and 52%, respectively, due to the end-of-pipe controls. (3) The contribution of the end-of-pipe controls to the emission reductions of primary PM_2.5, NO_x, NH₃ and NMVOCs is greater than that of the structural adjustments; while for SO₂ emission reduction, structural adjustments has played a greater role. Research demonstrated that the control of SO2 before 2030 should shift the focus from the end-of-pipe measures to the structural adjustment measures.