The severe air pollution in China has imperiled public health and resulted in substantial economic loss. To tackle the unprecedented pollution challenges, China has launched a campaign-based environmental inspection over all regions to impel local governments’ actual pollution abatement. At the same time, with the public’s awakening awareness about environmental protection, the public has also played a particularly vital role in this inspection. Under this circumstance, the study tries to reveal the impact of Environmental Inspection led by the Central Government (EICG) on air quality improvement, and to examine the role of public engagement in their relationship. Specifically, utilizing daily data covering 249 prefecture-level cities in China from 1 June 2015 to 31 May 2018, this study employed multiple regression models and then found that due to the implementation of EICG, the concentrations of PM2.5, PM10, SO2 and NO2 decline by 2.642 μg/m3, 6.088 μg/m3, 1.357 μg/m3 and 1.443 μg/m3, respectively, and the air quality index decreases by 2.4 in total, which implies that EICG can improve the air quality to a great extent. However, the coefficients for major variables change from negative to positive, suggesting that an attenuation effect of EICG on air quality improvement exists in Chinese institutional background. Meanwhile, public engagement is shown to enhance the positive association between EICG and air quality improvement. Additionally, further analysis demonstrates that EICG promotes the improvement in air quality up to three months after the inspection in cities during the heating period, while the positive effect has existed during one month before the inspection in cities during the non-heating period. Additionally, in contrast to the instant effect in cities not specially monitored, there is a lagged effect of EICG in controlling the air pollution in cities specially monitored.