In this study, the trend of PM_2.5 concentrations and its adverse health effects in China from 2001 to 2017 are estimated utilizing 1-km high-resolution annual satellite-retrieved PM_2.5 data. PM_2.5 concentrations for most of the provinces/cities remained stable from 2001 to 2012; however, following the issue of the Air Pollution Prevention and Control Action Plan (APPCAP) by the central government of China, a dramatic decrease in PM_2.5 concentrations from 2013 to 2017 occurred. Premature mortality caused by PM_2.5 dropped from 1,078,800 in 2014 to 962,900 in 2017. The PM_2.5 caused 17-year average mortality ranges from 3800 in Hainan Province to 124,800 in Henan Province. The health cost benefits gained by the reduction of PM_2.5 pollution amounted to US $193,800 in 2017 (compared to the costs due to PM_2.5 concentrations in 2013), amounting to 1.58% of the total national GDP. The impacts of urbanization on PM_2.5 concentration and mortality are analyzed. The PM_2.5 concentration and its induced mortality density in dense urban areas are much higher than those in rural areas. The aggravation of PM_2.5 associated premature mortality in urban areas is mainly due to the larger amount of emissions and to urban migration, and 6500 deaths in 2014 could have been avoided were the population ratios in dense-urban/normal-urban/rural areas to be reversed to the ones in 2001. It is recommended that people with respiratory-related diseases live in rural areas, where the pollutant concentration is relatively low.