Fe3O4/activated carbon fiber (F-ACF) was synthesized by a simple precipitation method and used as an adsorbent for tetracycline (TC) removal in aquaculture wastewater. The structural and chemical properties of the F-ACF were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive spectrometry (EDS) and Brunauer-Emmett-Teller (BET) analyses. Effects of various parameters such as solution pH (2-10), reaction time (0-24 h) and extra ion on TC adsorption onto F-ACF were investigated. The equilibrium result has shown that the adsorption was fitted well with Langmuir models compared to Freundlich models. The maximum Langmuir adsorption capacity was found to be 58 mg/g. The adsorption behavior of TC on F-ACF was best fitted with the pseudo-second-order kinetics model.