In this paper, amphiphilic snowman-like Janus particles and cobalt phthalocyanine catalyst were prepared, and the cobalt phthalocyanine catalyst was successfully loaded on the hydrophilic side of Janus particles selectively. The asymmetric structure of the particles with obvious partition was observed by SEM, and the components of the particles were further determined by XPS, EDS, FT-IR, TG, ect. The cobalt phthalocyanine modified amphiphilic Janus particles were applied as both solid particle emulsifier and interfacial catalyst for the photocatalytic degradation of water-soluble dye rhodamine B in a multiphase system. The factors of ventilation and light, catalyst dosage, initial concentration of dye and volume fraction of H₂O₂ influence the catalytic effect were investigated. The degradation rate of the dye was observed by UV-vis spectrophotometer. The results showed that the catalytic degradation rate of the Janus catalyst was up to 85.6%, showing a significant catalytic advantage over the pre-load catalyst. The catalyst was easily recovered for reuse, and maintained good catalytic efficiency for five cycles.