The invention discloses a mounting and dismounting tool for a V-shaped elastic piece of a leg tube. The mounting and dismounting tool comprises a tool main body, wherein the tool main body is of a cylindrical grip structure; the tool main body is divided into two front and rear parts, namely an operating part and a handheld part; the diameter of the operating part is smaller than that of the leg tube; the diameter of the handheld part is larger than the inner diameter of the leg tube; a lower strip-shaped groove through which one V-shaped elastic piece with an elastic piece top ball is inserted and limited is formed in a lower end face on the front section of the operating part along a length direction; an upper strip-shaped groove through which the other V-shaped elastic piece is bent tobe inserted and limit is symmetrically and concavely formed in the upper end face of the operating part; a popup stopper which pops up the lower end of the V-shaped elastic piece and is used for preventing the V-shaped elastic piece from popping up is arranged at a position, which is positioned at the tail end of the lower strip-shaped groove, of the lower end face of the operating part; an elastic piece pull-back screw fastened with the inner cavity of the elastic piece top ball on the V-shaped elastic piece to pull out is downwards convexly arranged at a position, which is positioned at thefront end of the lower strip-shaped groove, of the lower end face of the operating part. The mounting and dismounting tool disclosed by the invention is simple in structure, convenient to mount, detach and manufacture and low in cost, and the mounting efficiency of the V-shaped elastic piece can be effectively improved.