A trimmer head and a grass trimmer. The trimmer head comprises: a housing (10), a knocker head (20), and a wire reel (30). The knocker head comprise a knocker head body (21). The knocker head body is provided in a receiving cavity, and can rotate synchronously with the housing. The knocker head body is configured to operably move in the direction of the rotation axis of the housing, and the knocker head body can be connected to or disconnected from the housing in the process of moving in the direction of the rotation axis of the housing. The wire reel comprises a wire reel body (32) and an operation portion (34). The wire reel body is provided in the receiving cavity, and can rotate synchronously with the knocker head body. The operation portion extends out of the housing for the user to perform a rotating winding operation. The operation portion does not move in the direction of the rotation axis during the rotating winding operation. During this rotating winding operation, a wire rotating operation element performs a winding operation, and the operation portion does not move axially in the direction of the rotation axis of the housing, thereby further facilitating a screwing operation by the operation portion held with a hand； moreover, because the wire reel does not move axially with respect to the housing during wire pay-off, the pay-off stability is high and wire jamming is less likely to occur.La présente invention concerne une tête de coupe-bordure et un coupe-bordure. La tête de coupe-bordure comprend : un boîtier (10), une tête battante (20) et une bobine de fil (30). La tête battante comprend un corps de tête battante (21). Le corps de tête battante est disposé dans une cavité de réception et peut tourner de manière synchrone avec le boîtier. Le corps de tête battante est conçu pour se déplacer de manière fonctionnelle dans la direction de l'axe de rotation du boîtier, et le corps de tête battante peut être relié au boîtier ou déconnecté de celui-ci dans l
