Analysis　of　sectors＇　emission　effects　is　crucial　for　identifying　key　emission　sectors　and　reducing　carbon.　Current　literature　for　calculating　sectors＇　emission　effects　in　China　ignore　intermediate　demand.　This　might　introduce　inaccuracy　into　the　analyzed　results.　To　solve　this　gap,　this　paper　used　an　alternative　input-output　method　to　analyze　sectors＇　emission　effects　in　China.　Firstly,　it　identifies　the　key　emission　sectors　and　their　emission　effect　characteristics　from　2005　to　2017.　Then,　the　reasons　for　the　changes　in　these　sectors＇　emission　effects　are　analyzed.　Lastly,　emission　effects　were　further　decomposed　so　that　the　driving　relationships　of　emissions　among　these　sectors　can　be　sorted　out.　The　results　show　that　the　overall　key　emission　sectors　were　metal　smelting　and　processing　and　nonmetal　mineral　products.　The　backward-emission-dominant　sectors　were　construction,　chemical　products,　other　services　(such　as　finance,　health　and　education),　metal　products,　and　so　on.　The　forward-emission-dominant　sectors　were　production　and　supply　of　electricity　and　heat,　transportation,　storage,　postal,　and　telecommunications　services.　In　2017,　transportation,　storage,　postal,　and　telecommunications　services＇　own　final　demand　emissions　and　forward　emissions　accounted　for　41.7%　and　58.3%,　respectively,　of　this　sector＇s　direct　emissions.　Moreover,　from　2005　to　2017,　the　main　sector　emission　paths　affecting　the　growth　of　China＇s　emissions　shifted　from　manufacturing　and　construction　industries　to　service　industries.　Accordingly,　strategies　for　emission　reduction,　such　as　substituting　pollution　inputs,　were　proposed　and　analyzed.　The　research　provides　an　important　reference　for　the　Chinese　government　to　adopt　appropriate　measures　to　reduce　carbon.