A mower brake structure comprises a base (1). A motor (7) is fixed on the base (1), and the base (1) is rotatablely connected to an output shaft (41). A belt pulley (2) is disposed on the output shaft (41), and the output shaft (41) is driven by the motor (7) through a belt. A belt pulley liner (4) is disposed between the belt pulley (2) and the output shaft (41). The belt pulley liner (4) is fixed with the output shaft (41). A locking structure is disposed between the belt pulley (2) and the belt pulley liner (4). The locking structure enables the rotating belt pulley (2) to drive the belt pulley liner (4) to rotate. A spring (5) is disposed between the belt pulley (2) and the belt pulley liner (4). A friction structure is further disposed between the belt pulley (2) and the belt pulley liner (4). After the belt pulley (2) loses power, the spring (5) releases the elasticity so that the belt pulley liner (4) rotates reversely relative to the belt pulley (2), and the friction structure works. The belt pulley (2) and the belt pulley liner (4) can rotate relatively for certain displacement. During the rotation process, a protruding portion at an inner side of the belt pulley (2) provides pressure to or releases pressure from a movable friction block (3) assembled on the belt pulley liner (4), thereby effectively ensuring the reliable running of the brake structure. Therefore, the brake structure is compact and easy to operate, and the system is stable and reliable.Linvention porte sur une structure de frein de tondeuse à gazon, laquelle structure comprend une base (1). Un moteur (7) est fixé sur la base (1), et la base (1) est reliée en rotation à un arbre de sortie (41). Une poulie à courroie (2) est disposée sur larbre de sortie (41), et larbre de sortie (41) est entraîné par le moteur (7) par lintermédiaire dune courroie. Un chemisage de poulie à courroie (4) est disposé entre la poulie à courroie (2) et larbre de sortie (41). Le chemisage de poulie à courroie (4) e
