Rhodamine B (RhB), a toxic dye is environmentally hazardous and harmful to living organisms, which is primarily used in various industries. Multiferroic BiMnO3 (BMO) with (BMO 1) and without (BMO 2) surfactant (CTAB) was synthesized using hydrothermal method, which acts as a photocatalyst for the Rhodamine B dye degradation process. BMO had tested as a photocatalyst for dye degradation of Rhodamine B dye in UV and Visible light irradiation due to its narrow bandgap. On performing various structural and optical characterizations, the structure of as-prepared BMO samples confirmed, and their crystallite size and bandgap were compared for with and without CTAB treated BMO samples. Under UV irradiation, the decomposition of RhB efficiency and decay time had been calculated as 68% and 75 min for BMO 1. In H2O2 assisted visible light irradiation, BMO 2 shows better performance (90% and 55 min). © 2020, Springer Science+Business Media, LLC, part of Springer Nature.