The　theoretical　development　of　the　temperature　effect　of　the　full-section　asphalt　concrete　waterproof　sealing　structure　(ACWSS)　of　the　ballastless　track　subgrade　lags　the　engineering　practice.　In　order　to　reveal　the　passive　tensile　damage　behavior　of　ACWSS　from　the　perspective　of　theoretical　analysis,　in　this　paper,　the　base　plate　of　the　ballastless　track　and　the　ACWSS　is　simplified　into　an　elastic-viscoelastic　double　layer　composite　beam　model.　The　analytical　calculation　method　for　passive　tensile　damage　of　ACWSS　under　temperature　load　is　derived　theoretically.　The　change　of　surface　stress　and　strain　of　ACWSS　with　time　is　calculated　and　analyzed.　The　theoretical　analysis　and　calculation　results　show　that　the　variation　of　the　surface　strain,　the　maximum　strain,　and　the　time　corresponding　to　the　strain　peak　of　ACWSS　are　consistent　with　the　measured　results.　The　model　of　the　double-layer　composite　beam　has　high　reliability,　and　the　analytical　calculation　method　of　passive　tensile　damage　is　reasonable　and　practical.　The　temperature　stress　of　ACWSS　at　the　expansion　joint　of　the　base　plate　is　synchronized　with　the　temperature　change,　indicating　that　the　asphalt　concrete　at　this　location　is　mainly　subjected　to　axial　tension　(or　compression).　It　is　suggested　that　the　structural　design　should　be　judged　by　comparing　the　number　of　periodic　temperature　loads　and　the　allowable　fatigue　number　of　asphalt　concrete,　which　further　improves　the　design　method　and　technical　system　of　the　ACWSS　in　China＇s　high-speed　railway.　It　has　important　theoretical　and　practical　significance.