Sewage containing antibiotics is harmful to the water environment. Here, a newly prepared iron manganese binary oxide (FMBO) activated persulfate (PDS) has excellent performance for the degradation of sulfapyridine (SPY) in an aqueous environment. The effects of initial pH, SPY, PDS concentration and FMBO dosage on the degradation ability of SPY were investigated. When the pH of FMBO/PDS was 4.0 and the initial concentration of PDS was 2.0mmol/L, the degradation ratio of SPY could reach 94.4%. In the system of removing organic pollutants by transition metal activated PDS, SO4 -• and •OH radicals are generally generated, and •OH radical plays a major role. Through the identification of SPY intermediate products by LC/MS, the degradation mechanism was explored. The degradation pathway showed that the strong oxidation of FMBO and the activity of PDS promoted the production of hydroxyl radical and contributed to the degradation and transformation of antibiotics. This study shows that FMBO/PDS has high degradation efficiency in the degradation of SPY.