The utility model discloses a stake end expands end device, include drilling rod and the hydro -cylinder be connected with the motor: the support, its plectane that sets up for the level, well core rod, its cylindric structure that is vertical setting, its upper end is provided with the drilling rod and connects the interface, well core rod's lower extreme vertical fixation in the center of support, the beam barrel, its for cylindric and its inside have a coaxial flexible hole, the beam barrel passes through flexible hole slip cap is established well core rod's upper portion, first bearing, its inner circle slidable cover is established on the well core rod, its outer lane with the horizontal fixed connection in beam barrel upper end, the upper end of the inner circle of first bearing andthe vertical fixed connection of the piston rod of hydro -cylinder, a plurality of extension knife rests, the bracing piece, the cardboard. The utility model has the advantages of simple structure, multi -functional, but wide application in scene drilling bored concrete pile technique and equipment field.