Induced resistance of benzothiadiazole (BTH), a new inducer of plant disease resistance, to banana fusarium wilt caused by Fusarium oxysporum f.sp.cubense race 4 (Foc 4), was investigated. Firstly, in vitro toxicity of BTH to Foc 4 was tested with the growth rate method. The results showed that the EC50 of BTH was 929.9 μg/mL, showing a very weak antifungal effect compared to carbendazim, a routine fungicide. Secondly, the sensitivity of banana fusarium to BTH in three different concentrations was studied in vivo, and the results indicated that 50 μg/mL of BTH had the greatest effect of induced resistance with the disease control efficiency of 66.6%, and its control efficiency was descending gradually along with the increase of BTH concentration. Finally, the changes in activities of six defensive enzymes in banana plantlets treated with BTH were determined, and the results demonstrated that BTH could increase the banana resistance to banana fusarium wilt by improving the activities of several defense-related enzymes. Taken together,BTH is a promising plant disease resistance inducer by activating the defense response of banana plantlets. Therefore, BTH has a potential application prospect in the control of banana fusarium wilt disease.