To align the rotational center of chuck with tool tip is a very important operation procedure for precision turning, center alignment is difficult because the CNC lathe usually lacks of the device for the procedure. This paper presents a special structure of the tool shank for the CNC lathe. The structure which contains inclination and screw element provides tool shank with adjustable function. Thus, the tool shank not only easily changes the height of tool tip to align the center but also apply to traditional lathe to increase convenience and efficiency of the operation.