The utility model relates to a multi-tow fiber surface treatment device which is applied to fiber surface treatment. A five-layer frame is arranged on the side surface of a bracket, and two plasma generator power supplies and a mediation fan are fixed on the frame of each layer. Two cross beams are arranged at the upper part of the other side of the bracket; four godet wheels are arranged between the two cross beams; an arched trimmable spray gun supporting bracket is connected to the end parts of the two cross beams respectively; a spray gun group is fixed on the arched trimmable spray gun supporting bracket; the nozzle of the spray gun group is vertically opposite to the upper parts of the outer walls of the godet wheels; and a lead wire is connected between each plasma generator power supply and a spray gun. The multi-tow fiber surface treatment device has the effects that a low-temperature plasma generating device is adopted, the treatment is carried out on the fiber surface so as to realize continuous production, reduce fiber surface treatment procedures, simplifies the treatment process and improves the efficiency of the fiber surface treatment; and only electric energy and air are needed in the whole operation process, therefore, the clean and pollution-free process can be realized.