The invention discloses a device and a method for treating antibiotic drug wastewater by synergizing a Fe-C electrode with aerobic granular sludge. The device mainly comprises an electrode system, anaerobic granular sludge system, a water inlet system, an aeration system, a water outlet system and a time control system. The electrode system adopts an iron rod and a carbon rod with the height of 5to 10 cm and the diameter of 1 to 5 cm; Fe<2+> obtained by utilizing a DC power supply anode electrolytic iron rod can promote the activity of nitrifying bacteria and denitrification-related enzyme activity in the aerobic granular sludge, so that the Fe-C electrode synergizes with aerobic the granular sludge to realize good ammonia nitrogen treatment effect while reducing the antibiotic toxicity.The method disclosed by the invention comprises the following steps: at initial stage of startup, adjusting the DC power supply voltage to 1 to 2 V, setting the current to 0 to 1A and controlling theconcentration of the inoculated aerobic granules in a reactor to 4 to 6g/L; adding 0.1 to 5.0 mg/L of antibiotics into the wastewater; controlling the aeration quantity at 1 to 2 L/min, the volume exchange ratio of the reactor at 50 percent and the hydraulic retention time at 8 to 24 hours; at stable operation stage, enabling the effluent concentration of ammonia nitrogen and antibiotics to reachideal effects.