Abstract: Thirty-four substituted salicylanilides were prepared by condensation of substituted salols or salicylic acids with substituted anilines, or by nitration of a substituted salicylanilide with addition of a nitro-group at the 3-position on the salicyl nucleus. Nine substituted 2(o-hydroxy-phenyl)-benzimidazoles were prepared by condensation of substituted salicylic acids with o-phenylenediamine in presence of polyphosphoric acid at temperature between 120—250℃ for four hours. Some of the resulted compounds were screened in mice against schistosomiasis japonica. The results indicated that two compounds, 5, 2'-dichloro-4'-nitro-salicylanilide and 3, 5, 2' - trichloro-4'-nitro - salicylanilide showed chemoprophylactic activity, and the compound 3,5-diiodo-2',4'-dichloro-salicylanilide possessed chemotherapeutic activity.