A novel magnetically separable nano-BaFe2O4 was prepared as an effective catalyst for microwave (MW)-induced catalytic degradation (MICD) of crystal violet (CV), and its catalytic degradation mechanism and process were investigated. The nano-BaFe2O4 displayed enhanced catalytic activity for CV degradation under MW irradiation. The intermediates and final products were investigated by HPLC-MS and ion chromatography (IC), respectively. By combining the band structure and radical trapping studies, holes (h(+)), superoxide radicals (center dot O-2(-)), and hydroxyl radicals (center dot OH) were identified as the main active species in the reaction. The possible catalytic mechanism and process were proposed. The results showed that the catalytic activities of catalyst depend not only on its element constituents but also on chemical structure and energy band structure. This work provided some essential information on the catalytic behavior and mechanisms.