The　non-isothermal　case　in　bottom　composite　liners　not　only　induces　thermal　diffusion　behavior,　but　also　alters　transport　parameters.　To　date,　however,　limited　work　has　been　done　on　this　topic.　The　present　research　constructs　a　model　for　one-dimensional　non-isothermal　transport　of　organic　contaminant　in　the　three-layer　composite　liner　containing　a　defective　geomembrane　(GMB),　which　for　the　first　time　systematically　includes　the　impacts　of　temperature-dependent　transport　parameters,　and　also　considers　the　multiple　transport　mechanisms.　The　developed　model　is　then　solved　via　finite　difference,　and　its　rightness　is　well-proven　through　comparisons　with　the　two　experiment　results　and　the　other　calculation　approaches.　After　that,　the　numerical　analysis　shows　that　the　temperature-dependent　transport　parameters　exert　a　combined　effect　on　the　transport　process,　in　which　changes　in　diffusion　coefficients　and　hydraulic　conductivities　with　temperature　remarkably　accelerate　the　transport　rate,　whereas　such　a　change　for　distribution　coefficients　leads　to　an　opposite　trend.　The　barrier　performance　assessment　suggests　that　the　growth　of　temperature　difference　in　the　composite　liner,　as　well　as　the　GMB　defects　density,　reduces　the　defined　breakthrough　time　(tb)　and　increases　the　bottom　transport　flux.　Moreover,　1　cm　geosynthetic　clay　liner　is　noticed　to　extend　tb　by　approximately　2.23　years,　while　0.1　m　compacted　clay　liner　yields　the　increment　of　tb　by　about　12.1　years.　These　findings　contribute　to　the　reasonable　evaluation　of　bottom　composite　liners’　barrier　performance　at　a　non-isothermal　environment,　which　could　provide　guidance　for　optimizing　their　engineering　design.　©　2024　Elsevier　Ltd