In this study, syderolite (Sd) pellets loaded with bimetallic oxides (Sd-Ni-Co) catalyst was prepared for the first time, which was used to activate peroxymonosulfate (PMS) for the degradation of Brominobenzonitrile (BMN). The effects of the Sd-Ni-Co dose, PMS dose, pH value, BMN concentration, and different anions on the degradation experiment were explored. The optimal reaction conditions for the degradation of 50 mg/L BMN were 100 g/L Sd-Ni-Co and 0.2 g/L of PMS, and the degradation was complete at room temperature within 40 min. The ten continuous cycle test shows the perfect structural stability of Sd-Ni-Co. Sd-Ni-Co/PMS system not only shows a good degradation performance on BMN but also on other organics, indicating that the method has a good universality. The radical quenching experiments (ethanol and tert-butanol) show that both •OH and SO₄^-·play an important role in this reaction system, and further confirmed the result by electron paramagnetic resonance (EPR) spectra. The Sd-Ni-Co was characterized by SEM, XRD, XPS, and BET. The degradation process was analyzed by triple quadrupole liquid chromatography-mass spectrometry (LC-MS), and the possible degradation pathway and mechanism were proposed.