Abstract: The allelopathic effect from extracts from cassava organ on the banana Fusarium oxysporum f. sp. cubense was investigated by growth rate method in the paper. The aboveground and underground parts of cassava organ during the stage of root formation were extracted by ethanol and water, respectively. The results showed that the extracts had inhibition to the banana F. oxysporum f. sp. cubense either by ethanol or by water, and there was no significant difference between ethanol and water, the inhibition effect of underground organ was stronger than that of the aboveground. The effects of 50 -100 mg/L extracts were stronger, while the effect decreased with the time increasing, the effect at 24 h was higher than that at 72-120 h significantly.