Abstract: The results showed that using 32.7% of SMDC(a soil fumigant)on seed-bed of flue-cured tobacco had signifcant effect for controlling the common weeds of the seed-bed.The effect of eliminating the weeds:using 25ml/m² of SMDC was 71.9%, 50ml/m² was 87%, 75ml/m² reached to 88.1% and using 100ml/m² controlling effect reached to 89.6%.This product is safe both to the seeds germination and the seedlings, as well as personnel that conducting the application, it may be used as an alternative to the weeds removing by hand for seed-bed.The suitable rate can be 50~70ml/m².