Abstract: In order to raise tea seedlings by cutting nursery on original soil instead of paving subsoil on seedbed, a test was implemented by covering mulching film on nursery land at some periods in summer to kill harmful microorganisms in the surface soil by hot humid air under the film in sunny days. The temperatures of the surface and the 5 cm depth under the film were observed after covering the film. The maximum temperature of the surface under the film in sunny days could reach 65.0℃, and that at the 5 cm depth could be up to 54.2℃. Under laboratory conditions, the soil sample was treated under the temperature which was observed under the film. As a result of continuously and intermittently high temperature circulation, more than 95% of the fungi in the surface soil were killed when the soil temperature was (50±1)℃ at the 5 cm depth and lasted two hours per day for 7-10 days. Meanwhile, the growth of other harmful microorganisms was inhibited. After 5 months of cuttage, the healing ratio in seedbed with mulching film was 82.9%, the seedling rate was above 55.1%, which was equal to that in the seedbed with paved subsoil. Furthermore, the direct cost could be cut for more than ￥15000 per hectare. Therefore, mulching film in summer can be widely used for the disinfection of tea cuttage soil.