In order to study the effects of 7 kinds of fumigant，such as metham sodium，dazomet，calcium
cyanamide，methanal，1，3-dichloropropylene，dimethyl disulfide and methyl iodide on Fusarium oxysporum
in soilless culture substrates after treatment at different times and with different concentrations，the experiments
determined the quantity changes of Fusarium oxysporum with dilution plate method through indoor culture
experiments. The results showed that all 7 kinds of fumigant could significantly reduce the number of Fusarium
oxysporum. After 5 days fumigation with 120 mg·L^-1 42% metham sodium and 300 mg·L^-1 98% dazomet，the
killing rate could reach up to 100.00%；after 8 days fumigation with 50 times diluted 40% methanal，800 mg·L^-1
calcium cyanamide，400 mg·L^-1 dimethyl disulfide，150 mg·L^-1 1，3-dichloropropylene and 300 mg·L^-1
methyl iodide，the killing rate could reach 99.07%，98.71%，96.57%，94.86% and 85.00%，respectively.
Thus，all 7 kinds of fumigant had some effects on Fusarium oxysporum，and metham sodium and dazomet had the
most significant effect on controlling Fusarium oxysporum at soilless culture substrates，and yet with very short
fumigation time. The next effective were methanal and calcium cyanamide.