An activated carbon filter device for sewage treatment comprises a filter tank, an activated carbon filter net, a sedimentation tank, fixing bolts, a gate and a water outlet pipe, wherein a filter net groove is formed in the middle of the filter tank, filter net inserting slots are uniformly distributed in the filter net groove, conical inserting head grooves are symmetrically distributed in the filter net inserting slots, conical bosses are symmetrically distributed at the bottom of the activated carbon filter net and inserted into the conical inserting head grooves, filter net outer frames are symmetrically distributed in the middle of the activated carbon filter net, slider grooves are symmetrically distributed in the filter net outer frames, sliders are uniformly distributed in the filter net grooves and inserted into slider grooves, the sliders slide in the slider grooves, a connecting top plate is arranged at the top of the activated carbon filter net, top plate inner holes are uniformly distributed in the connecting top plate, filter net groove side plates are symmetrically distributed on two sides of the filter net groove, internal threaded grooves are uniformly distributed in the filter net groove side plates, the fixing bolts are inserted in the top plate inner holes and the internal threaded grooves, and the filter tank is connected with the activated carbon filter net.