Five novel benzothiazole derivatives( 4a ~ 4e) were designed and synthesized from 2-aminobenzenethiol and 4-aminobenzoic acid. The structures were characterized by ~1H NMR,IR,MS( EI)and elemental analysis. The preliminary bioactivities of 4a ~ 4e were investigated by mycelium growth rate method. The results showed that,to some extent,4b( 47%) and 4e( 43%) exhibited fungicidal activities against watermelon fusarium oxysporum with dosage of 100 mg·L~(-1).