The invention relates to the technical field of twining of yarn, and discloses a device for improving the softness and strength of the yarn. The device comprises a shell, a yarn tensioning pillar is movably connected to the interior of the shell, a ventilation pipeline is hinged to the surface of the yarn tensioning pillar, and yarn winding pillars are movably connected to the two sides of the ventilation pipeline; air blowing ports are movably connected to the interiors of the yarn winding pillars, cooling pipelines are fixedly connected to the two sides of each air blowing port, a yarn outlet nozzle is movably connected to the side, away from the ventilation pipeline, of each yarn winding pillar, and a yarn guiding port is fixedly connected to the interior of each yarn outlet nozzle. Theyarn tensioning pillar is also driven to rotate, and conducts primary twisting on the yarn entering the yarn tensioning pillar from the right side, and then the yarn temporarily winds the yarn tensioning pillar, and afterwards, breaks away from the yarn tensioning pillar and winds the yarn winding pillars to be subjected to secondary twisting; the yarn winding the yarn winding pillars finally flows out of the yarn guiding ports in the yarn outlet nozzles, and then the yarn outlet nozzles are driven by rotation balls to rotate for third-time twisting. By means of the device, the effect of improving the twisting strength is achieved.