Abstract: A process for preparing a bulk powder for an oxide superconductor which comprises mixing an alcohol solution (I) of a copper nitrate and a lanthanoid metal nitrate with an alcohol solution (II) comprising at least one compound selected from the group consisting of a barium hydroxide and a barium alkoxide to give a coprecipitate, and thermally decomposing the coprecipitate. According to the present invention, compared to the solid-state reaction, fine particles having the particle size of not more than 1 .mu.m can be easily produced because barium carbonate comparatively stable to heat is not formed on calcination, and the desired bulk powder for oxide superconductor can be produced at even lower temperature. Consequently, the obtained bulk powder for the oxide superconductor has fine particles, e.g. the particle size being not more than 1 .mu.m, therefore, the powder is excellent in stoichinometry, large in surface energy and excellent in sintering property.