Owing　to　global　climate　change　and　increased　environmental　pollution,　China　faces　the　dual　responsibility　of　reducing　CO2　emissions　and　controlling　PM2.5　pollution.　This　study　compares　the　spatial　characteristics　of　PM2.5　concentrations　and　CO2　emissions　using　10　km　x　10　km　grid　data.　The　increase　and　decrease　of　CO2　emissions　and　PM2.5　concentrations　are　divided　into　four　quadrants,　which　indicates　four　different　conditions.　Then,　spatial　autocorrelation　method　is　conducted　to　analysis　the　spatial　relationships.　The　empirical　results　show　that　(1)　In　the　four　quadrants,　the　increase　of　CO2　emissions　and　the　decrease　of　PM2.5　concentrations　accounted　for　the　highest　proportion　(25.9%).　(2)　The　spatial　differences　in　CO2　emissions　are　large,　but　the　PM2.5　concentrations　show　strong　spatial　aggregation.　(3)　China＇s　three　major　urban　agglomerations　contain　more　than　half　of　the　areas　in　which　both　CO2　emissions　and　PM2.5　concentrations　increased,　and　the　Pearl　River　Delta　urban　agglomeration　exhibits　the　best　synergistic　reduction　effect.　By　contrast,　the　Beijing-Tianjin-Hebei　urban　agglomeration　has　the　worst　synergistic　reduction　of　CO2　emissions　and　PM2.5　concentrations.　(4)　At　the　urban　level,　as　a　typical　city　in　the　Beijing-Tianjin-Hebei　urban　agglomeration,　Tianjin＇s　overreliance　on　heavy　chemical　industries　has　led　to　co-increases　in　its　CO2　emissions　and　PM2.5　concentrations.　Shaoxing　and　Jiangmen,　in　the　Yangtze　River　Delta　and　Pearl　River　Delta　urban　agglomeration,　are　among　the　few　cities　where　CO2　emissions　and　PM2.5　concentrations　have　both　been　reduced.　Finally,　this　paper　suggests　some　policy　implications　of　these　findings.