Abstract: The thesis aims to study the biological characteristics of Fusarium oxysporum, which is isolated and purified from Pachira macrocarpa. The results showed that the growth rate of F. oxysporum varied under different temperature (27℃>24℃>30℃>33℃>36℃>40℃), and the respective growth rate was: 97.93%> 95.48%> 12.75%> 4.93%> 2.23%> 1.48%, and the optimum growth temperature for F. oxysporum was 27℃. Growth velocity mensuration containing poisonous medium culture was used to screen various fungicides that could inhibit the growth of F. oxysporum. The results showed that: the fludioxonil reached the highest inhibitory rate (80.87%) atthe effective concentration of 62.5mg/L under1000timesdilution,andEC50 valuewas64.59mg/L. The chemical toxicity regression was Y=4.351+0.359x calculated using the least square method. Azoxystrobin at the effective concentration of 250 mg/L under 1000 dilution, reached the highest inhibitory rate of 74.19%, and the EC50 value was 78.17 mg/L. The virulence regression equation was: Y=2.419+1.363x. Thiophonatemethyl inhibited the pathogen most effectively (85.80%) at the concentration of 700 mg/L under 1000 times dilution, the EC50 value was 202.61 mg/L and toxicity regression equation was Y=0.575+1.919x.