The invention relates to a controllable stretching and contracting type electric drill. The controllable stretching and contracting type electric drill comprises an action unit, a control unit, a buffer unit and a main body unit, wherein the action unit is connected to the upper end of the control unit through screw threads, the lower end of the control unit is connected to the upper end of the main body unit through screw threads, the buffer unit is connected to the left end of the main body unit through screw threads, when a button is pressed, a switch control block is pushed to move inwards, and then stretching and contracting blocks are pushed to move inwards, when the stretching and contracting blocks move to be withdrawn into a spline shaft completely, the spline shaft is made to move up and down by pulling the action unit, the button is loosened, the switch control block is reset under the action of a spring b, when the stretching and contracting blocks on the spline shaft and an outer tube a stretch into an inner spline tube and an outer tube b under the actions of springs a correspondingly, the spline shaft is fixed, and the electric drill operates normally while control of the electric drill stretching and contracting length is realized. According to the controllable stretching and contracting type electric drill, the electric drill stretching and contracting length is adjusted according to the operating environment, the controllable stretching and contracting type electric drill is suitable for operating in a narrow space and other complex environments, and the hole drilling convenience is improved.