The microbe leaching-out method uses the strain of ferrous oxide thiobacillus, sulfur oxide thiobacillus or their mixture; Leathen culture medium and textile dye sewage culture medium; pyrite ferrous sulfate or sulfur element as reductant; and mycetophilous pyrite lixiviant for pH regulation. The polymetal nodule without being dried and ground is leached out directly with the acclimated bacterial at normal temperature and acid condition.