Under　the　multiple　pressures　of　climate　change,　carbon　mitigation　and　economic　development,　systematically　studying　the　compound　effects　of　economic　and　environmental　policies　on　the　system　is　desired.　An　interactive　multi-region　enviro-economic　equilibrium　(IMR3E)　model　is　developed　to　i)　explore　various　carbon-mitigation　effects　(and　their　interactions)　under　multiple　policy　alternatives　(in　terms　of　carbon,　income　and　production　taxes)　and　their　combinations.　ii)　characterize　interactions　among　sectoral　activities　of　multiple　provinces,　as　well　as　their　inner-　and　inter-region　social-economic　and　environmental　(SEE)　effects.　It　is　discovered　that　about　20　%　of　the　carbon　emission　of　the　Yangtze　River　Economic　Belt　is　to　meet　the　final　demands　in　other　provinces　(mainly　in　Guangdong　and　Beijing)　outside　the　YREB.　The　power　generation　sector　and　the　non-metallic　mineral　products　industry　(including　the　cement　industry)　are　the　main　sources　of　external　carbon　emissions.　Moreover,　the　composite　effects　of　the　implementation　of　different　enviro-economic　policies　in　YREB　will　be　amplified　along　with　the　supply　chain,　and　are　reflected　in　the　impact　on　carbon　emissions　of　different　provinces.　The　adjustment　of　YREB＇s　production　tax　and　carbon　tax　will　have　a　certain　impact　on　the　indirect　emission　intensity　of　other　provinces,　while　the　income　tax　will　not.　For　system　symbiosis　(i.e.,　an　ecological　indicator　that　reflects　the　fitness　of　the　entire　system),　adjusting　production　tax　is　the　most　important　factor,　and　a　lower　production　tax　level　is　the　most　beneficial.　Regarding　the　consumption-based　carbon　emission　intensity　of　other　provinces,　carbon　tax　policy　has　the　greatest　impact,　with　a　contribution　rate　of　over　95　%.　Moreover,　the　interaction　of　carbon　tax　and　production　tax　should　be　fully　valued　when　adjusting　the　industrial　structure.