The invention discloses a light thermal-insulation impervious pressure-bearing door and window frame joint sealant as well as a preparation method, a use method and application thereof. The door and window frame joint sealant is prepared from high-molecular polymer rubber powder, polyphenyl granules, cement, quartz powder, heavy calcium carbonate, kaolin, a powder defoaming agent, composite fibers, a water-retention thickening agent, starch ether and a water reducing agent. Wherein the composite fibers are polypropylene fibers, steel nanofibers and carbon fibers; the problems of water seepage, cracking, poor adhesion, poor load bearing and the like after seam filling of the door and window frame can be solved, and meanwhile, the high-strength light-weight performance is considered, the construction performance is high, no hanging is left, and the effects of high impermeability, high load bearing and high heat preservation are achieved. The preparation method of the door and window frame caulking glue comprises the following steps: mixing the components, stirring at a high speed to obtain a powdery finished product, and finally bagging and storing, the process is simple and convenient, the door and window frame caulking glue is suitable for large-scale production, and the transportation energy consumption can be greatly reduced.