As　wind　power　develops　by　leaps　and　bounds,　its　uncertainty　has　posed　huge　challenges　for　operational　planning　for　integrated　electricity-gas　system　(IEGS).　An　approach　based　on　affine　arithmetic　(AA)　for　optimal　power-gas　flow　(OPGF)　considering　uncertainty　of　wind　power　is　proposed.　Based　on　convex　envelope,　AA-based　OPGF　model　is　developed　without　non-affine　operations.　Uncertain　wind　power　is　treated　by　affine　form　keeping　track　of　relationships　between　uncertain　variables.　By　introducing　AA　theory,　AA-based　OPGF　model　can　be　converted　into　deterministic　multi-objective　problem.　Then　a　tightening　convex　envelope　algorithm　is　employed　to　enhance　solution　feasibility　of　AA-based　OPGF.　Numerical　results　demonstrate　the　effectiveness　of　the　proposed　AA-based　method　compared　with　Monte　Carlo　method.　In　addition,　the　transmission　tracks　of　uncertain　factors　are　also　revealed.　©　2023　IEEE.