The　energy　flow　coupling　of　integrated　energy　system　is　getting　closer.　Meanwhile，the　strong　uncertainty　of　renewable　energy　and　load　demand　bring　challenges　to　the　energy　flow　analysis　of　system.　Therefore，an　affine　interval　energy　flow　algorithm　of　the　integrated　electricity　and　natural　gas　system　（IEGS）　is　proposed，which　preserves　the　characteristics　of　noise　elements　in　the　calculation　results　of　affine　energy　flow，and　the　influence　degree　of　independent　uncertain　elements　on　state　variables　of　system　through　noise　element　coefficient　is　analyzed.　The　affine　models　and　energy　flow　equations　of　electricity　and　natural　gas　subsystems　are　established.　The　prediction-correction　affine　energy　flow　algorithm　of　IEGS　based　on　the　region　contraction　idea　is　proposed.　The　solution　domain　of　state　variable　is　conservatively　predicted　according　to　sensitivity，and　the　optimal　model　is　constructed　to　compress　and　correct　solution　domain.　Moreover，the　distributed　iterative　method　of　multi-energy　flow　is　adopted　to　solve　the　model，which　does　not　need　to　consider　the　multi-energy　flow　calculation　sequence　in　the　complex　coupling　system.　Finally，the　simulative　results　verify　the　advantages　of　the　proposed　method　in　terms　of　conservatism　and　computational　efficiency.　Furthermore，the　influence　of　uncertain　element　on　state　variables　of　system　is　quantitatively　analyzed.　©　2024　Electric　Power　Automation　Equipment　Press.　All　rights　reserved.