To　deal　with　the　optimal　dispatch　problem　of　combined　electric　and　heat　system　considering　multiple　uncertainties,　this　paper　proposes　a　two-layer　affine　optimization　method,　which　can　reduce　the　conservativeness　of　the　dispatch　scheme,　improve　the　economy　of　the　optimization　results,　and　reveal　the　influence　mechanism　of　uncertainty　sources.　First,　a　linear　energy　transmission　model　is　established,　and　an　interval　linear　programming　method　is　developed　to　solve　the　upper-layer　uncertain　unit　commitment　problem.　In　this　way,　the　interval　expansion　caused　by　nonlinear　operations　is　avoided.　Then,　the　linear　energy　transmission　model　considering　network　loss　is　established　by　Taylor　expansion.　Furthermore,　the　system　operation　constraints　are　defined　based　on　affine　arithmetic,　and　the　lower-layer　uncertain　economic　dispatch　problem　is　solved　by　the　affine　optimization　method.　Additionally,　the　proposed　method　can　keep　track　of　uncertainty　sources　and　quantify　their　influence　on　economic　dispatch　problem.　Finally,　the　simulations　are　carried　out　on　the　modified　33-nodes　Barry　Island.　The　results　show　that　the　proposed　method　can　effectively　reduce　the　conservativeness　of　the　dispatch　scheme　and　the　operating　cost　of　the　system　compared　to　the　interval　optimization　method.　©2023　Chin.Soc.for　Elec.Eng.