With the completion of the Beijing Five-year Clean Air Action Plan by the end of 2017, the annual mean PM<sub>2.5</sub> concentrations in Beijing dropped dramatically to 58.0 μg/m<sup>3</sup> in 2017 from 89.5 μg/m<sup>3</sup> in 2013. However, controversies exist to argue that favorable meteorological conditions in 2017 that helped pollution dispersion were the major factor for such rapid decrease in PM<sub>2.5</sub> concentrations. To comprehensively evaluate this five-year plan, we employed Kolmogorov-Zurbenko (KZ) filtering and a WRF-CMAQ model to quantify the relative contribution of meteorological conditions and the control of anthropogenic emissions to PM<sub>2.5</sub> reduction in Beijing from 2013 to 2017. For these five years, the relative contribution of emission-reduction measures to the decrease of PM<sub>2.5</sub> concentrations in Beijing calculated by KZ filtering and the WRF-CMAQ model was 80.6 % and 78.6 % respectively. The WRF-CMAQ model further revealed that local and regional emission-reduction measures contributed to 53.7 % and 24.9 % of the PM<sub>2.5</sub> reduction respectively. For local emission-reduction measures, the regulation of coal boilers, increasing clean fuels for residential use, industrial restructuring, the regulation of raise dust and vehicle emissions contributed to 20.1 %, 17.4 %, 10.8 %, 3.0 % and 2.4 % of PM<sub>2.5</sub> reduction respectively. Both models suggested that the control of anthropogenic emissions contributed to around 80 % of the total decrease in PM<sub>2.5</sub> concentrations in Beijing, indicating that emission control was crucial for the notable improvement in air quality in Beijing from 2013 to 2017. Therefore, such long-term air quality clean plan should be continued for the future years to further reduce PM<sub>2.5</sub> concentrations in Beijing. Considering that different emission-reduction measures exert distinct effects on PM<sub>2.5</sub> reduction and existing emission-reduction measures work poorly to reduce ozone concentrations, future strategies for emission-reduction should be designed and implemented accordingly.