The invention discloses an improved letter box processing device. The improved letter box processing device comprises an assembly rack which is mounted in a hanging bracket in a matched manner by translating left and right and a working rack which is firmly locked to the assembly rack in matched connection, wherein a translational hanging slot which is opened downward and extends left and right isformed in the hanging bracket; the upper end of the assembly rack is mounted in the translational hanging slot in a left and right translating manner, and a screw in the assembly rack is matched witha screw column; the end surface of the right part of the screw column is rotatably connected to the inner wall of the right side of the hanging slot in a matched manner; the end surface of the left part of the screw column is connected to a motor mounted and fixed to the hanging bracket in a matched manner; a hanging rod is fixedly mounted in a position right above the end surface of the upper part of the hanging bracket; a sink groove which extends upward is formed in the end surface of the bottom of the left side of the working rack; a sliding rack is translationally connected in the sink groove in a matched manner; and a sunken groove is formed in the end surface of the bottom of the right side of the working rack. The improved letter box processing device disclosed by the invention issimple in structure and convenient to operate, can be automatically controlled to be locked firmly and connected in a matched manner, and is convenient to detach and mount, and meanwhile, the work efficiency of labeling work is improved.