Sulfamethazine (SMT) is widely used in human and veterinary medicine as growth promoters and antibacterial drugs and it can pose potential threats to human and ecosystem health. In this study, removal of SMT by ultrasound pre-magnetized Fe-0/PS process was investigated for the first time. Degradation rate for removing SMT increased 3.3 folds and the synergy factor increased from 1.2 to 2.7 compared with US/Fe-0/PS process. Affecting factors such as pH (3-10), Fe-0 dosage (0-0.8 mM) and initial SMT concentration (0-10 mg L-1) were studied. Stronger signals of DMPO-OH and DMPO-SO4 adduct also illustrated more and faster SO4 center dot- and (OH)-O-center dot radicals produced in the system. FeOOH was detected through the mossbauer spectrum which could both enhance the catalysis of H2O2 and activation of PS. The intermediates of the SMT degradation were investigated, and a degradation pathway was proposed. Higher correlation factor (Delta k and Delta S) in US/pre-magn-Fe-0/PS system illustrated the good synergistic effect between US input power and magnetic field. Moreover, the process could efficiently remove SMT in municipal wastewater and keep pH neutral. So, US/pre-magn-Fe-0/PS process is a energy saving and promising approach to remove antibiotics in real wastewater.