On the basis of the structure, principle, control method of the horizontal boring machine,the transmission system and implementing mechanism of T6112 horizontal boring machine are designed. According to the principle of the horizontal boring machine, in which the motor is the power source, combining with the four directional movements of the machine, that is the up and down movements of main shaft, the horizontal and vertical movement of work table, then complete the processing of the work piece. The structure and technical parameters of the horizontal boring machine are given and the overall structure is designed. According to the horizontal boring machine design, this paper describes the design of implementing mechanism and the transmission system, including the selection of motor specification, the design of spindle gearshift, bed and work table.