Since the reform and opening up, China's economy has developed rapidly, which has also caused environmental problems such as industrial emissions. PM_2.5 (particulate matter with a diameter of less than 2.5 microns) emissions seriously threaten people's health. Therefore, it is necessary to study the emission reduction of PM_2.5. This study combines the Data Envelopment Analysis (DEA) and Logarithmic Mean Divisia Index (LMDI) methods to originally construct the inequality indicator and explore the influence of different factors on the inequality of per capita PM_2.5 from the regional aspect. This study decomposes the “emission efficiency” of per capita PM_2.5 emissions into more important effects. It reveals that, in East China, the energy-oriented technology gap (ETG) had the strong reducing effect on the national per capita PM_2.5 emissions; the energy-oriented technology efficiency (ETE) and economic development level (EDL) had the strong promoting effect. In Central China, the potential emission intensity (PEI) has the strong reducing effect on the national per capita PM_2.5 emissions, followed by the EDL; the ETG and energy-biased technology (EBT) effect had the strong promoting effect. In West China, the ETE had the strong reducing effect on the national per capita PM_2.5, followed by the PEI; the ETG had the strong promoting effect, followed by the EBT and output-oriented technology gap (YTG). The ETE had the greatest improving effect on the inequality indicator, and the PEI and EDL had the greatest reducing effect. Policy suggestions are put forward based on regional differences in East China, Central China and West China.