A series of cobalt ferrite/reduced graphene oxide (CoFe2O4/rGO, CFOG) magnetic nanocomposites were synthesized, and the morphological, structural, and surface chemical properties were characterized. The as-prepared materials exhibited excellent photocatalytic activity under LED illumination, and could also be applied as catalyst of SR-Fenton system to generate sulfate radical for the degradation of organic pollutants. Herein, we constructed a CFOG/LED/PMS system for the activation of peroxymonosulfate (PMS) to degrade organic contaminants under LED irradiation. The effects of key factors (PMS concentration, catalyst dosage, initial pH) were evaluated through the degradation of Carbamazepine (CBZ) in CFOG/LED/PMS system. Besides, the radical quenching experiments, ESR experiments and XPS analysis were utilized to investigate the degradation mechanism of oxidizing CBZ in CFOG/LED/PMS system. And the possible degradation pathways were proposed by the intermediates detected by HPLC-MS. The excellent degradation performance of Tetracycline, Rhodamine B, and Congo Red further confirmed that CFOG/LED/PMS system possessed wide applicable for the removal of organic pollutants, providing a promising option for the wastewater treatment technology.