Effectiveness testing and evaluation are crucial issues in regional environmental coordinated governance. Based on the air quality index and monthly data of six sub-pollutants, including fine particulate matter (PM), respirable particulate matter (RPM), sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), and ozone (O3), from 2013 to 2018, this paper evaluates the implementation effectiveness of regional coordinated governance with the first batch of 73 cities implementing the new environmental air quality standards as the research subjects. The results show that the effectiveness of regional environmental coordinated governance varies across different regions and environmental indicators. The coordinated governance does not effectively improve the overall air quality at the national level, but reduces sulfur dioxide concentration. The coordinated governance achieves the expected effects of improving the comprehensive air quality and reducing sulfur dioxide in the Beijing-Tianjin-Hebei region. Additionally, it significantly reduced the concentrations of inhalable particulate matter, sulfur dioxide, and carbon monoxide in the Yangtze River Delta region. Based on these findings, beneficial suggestions for improving China’s environmental governance policies are proposed.