Sulfadiazine (SDZ) is frequently detected in environmental samples, arousing much concern due to its toxicity and persistence. This study investigated the electricity generation capabilities, SDZ removal and microbial communities of highly efficient mixed-cultures using repeated transfer enrichments in a bio-electrochemical system. The mixed-culture biofilm (S160-T2) produced a remarkable current density of 954.12 ± 15.08 μA cm-2 with 160 mg/L SDZ, which was 32.9 and 1.8 times higher than that of Geobacter sulfurreducens PCA with 40 mg/L SDZ and without additional SDZ, respectively. After acclimation, the bioreactor achieved an impressive SDZ removal rate of 98.76 ± 0.79% within 96 h. The removal efficiency using electrochemical system was 1.1 times higher than that the anaerobic biodegradation. Furthermore, the current density and removal efficiency in this system gradually decreased with increasing SDZ concentrations from 0 to 800 mg/L. In addition, Community diversity data demonstrated that the dominant genera, Geobacter and Escherichia-Shigella, were enriched in mixed-culture biofilm, which might be responsible for the current production and SDZ removal. This work confirmed the important roles of acclimatized microbial consortia and co-substrates in the simultaneous removal of SDZ and electricity generation in an electrochemical system.