Abstract: The precipitation behavior of copper-enriched phases at different temperatures in Fe-Cu alloys and the effect of MnS inclusions on it were investigated by SEM analysis. The samples were heated to 1600℃ and kept for 20 min, some of them were waterquenched directly, and the others were furnace-cooled to a predetermined temperature and kept for 20 rain and then quenched. The results showed that in Fe-7.8% Cu alloys, copper-enriched phases precipitated both inside grains and at grain boundaries after water-quenched at 1 600℃, copper-enriched phases precipitated mostly at grain boundaries while water-quenched at 1 200℃, and there were ε-Cu phases with large size precipitates at grain boundaries after water-quenched at 1 000℃. In Fe-2.1% Cu alloys, copperenriched phases precipitated at grain boundaries after water-quenched at 1 600℃ and 1 000℃, and e-Cu phases were found inside grains after water-quenched at 800℃. MnS inclusions could be the effective nucleation substrate of copper precipitation in the alloys.