Abstract: Four novel benzothiazole-phosphites were prepared from benzothiazole derivatives.Their structures were confirmed by IR,NMR and elemental analysis.The inhibitory effects and mechanisms of action of four benzothiazole-phosphites to Fusarium graminearum in vitro were studied with the mycelial growth rate method.The results showed that four salts had high inhibitory effect on the growth of Fusarium graminearum,with the value of EC50 ranged from 15.2 to 36.1 μg/mL.After F.graminearum was treated with 100 μg/mL of 2-amino-6-methoxybenzothiazole-phosphite(D),the hyphal morphology was observed abnormal and swollen after 3 days.After 8 days,part of the hypha and ramification was shriveled and collapsed,and the surface of mycelium was blurred and unshaped.After treatments with four salts at(300 μg/mL) within(12 h),the mycelial reducing sugar content declined obviously and chitinase activity increased significantly.And the soluble protein and D-GlcNAc content increased in the short time and decreased subsequently.