The invention discloses a three-segmented telescopic self-locking spontoon. The spontoon comprises an outer tube, a middle tube, an inner tube, a striking protruding head, multi-
petal-shaped buckle assemblies, a positioning spring, a multi-
petal-shaped expansion circle spring, a starting guide rod and a starting button. The spontoon is characterized in that the starting button controlling a sleeve to stretch and retract is installed at the bottom end of the outer tube, the starting guide rod is arranged in the outer tube and is connected with the starting button, the middle tube is assembled in the outer tube, the inner tube is assembled in the middle tube, and the multi-
petal-shaped buckle assemblies, the positioning spring and the multi-petal-shaped expansion circle spring are installed at the position, at the bottom end of the middle tube, in the outer tube and at the position, at the bottom end of the inner tube, in the middle tube. Each multi-petal-shaped buckle
assembly comprises two or more buckle block annular arrays, the tops of buckle blocks are buckle conical arms, buckle limiting protrusions are arranged on the outer sides of the middles of the buckle blocks, buckle locking protrusions are arranged on the outer sides of the
tail portions of the buckle blocks, a positioning spring clamping groove and an expansion circle spring clamping groove are formed in the inner sides of the buckle blocks, the positioning spring is installed in the positioning spring clamping groove, the multi-petal-shaped expansion circle spring is installed in the multi-petal-shaped expansion circle spring clamping groove, and the striking protruding head is installed at the top end of the inner tube.