A trocar (1000) comprising two protective covers. The trocar comprises a puncture needle (200) and a cannula assembly (100)； the cannula assembly (100) comprises a hollow cannula (130)； the hollow cannula (130) comprises a distal cannula end (132) and a cannula lip (131)； the puncture needle (200) comprises a handle part (202), a distal part (206), and a rod part (204) therebetween； during operation of the trocar, the puncture needle (200) runs through the cannula assembly (100) and is used for piercing through the body wall of a patient so as to establish a puncture channel； the distal part (206) comprises a fixed protective cover (250), a working edge (220), and a movable protective cover (280)； the rod part (204) comprises a fixed rod (310) and a movable rod (320)； the fixed protective cover (250) comprises a fixed cover base body (254) and a fixed cover inclined distal end (260) connected with the fixed cover base body； the fixed cover inclined distal end (260) comprises a distal shaft hole (258)； the distal shaft hole (258) pierces through the fixed cover inclined distal end (260) to form a fixed cover lip (266)； the fixed protective cover (250) is connected with the fixed rod (310)； the working edge (220) extends towards a proximal end and is connected with the fixed rod (310) or the handle part (202)； the working edge (220) extends towards the distal end and goes beyond the fixed cover lip (266).Cet instrument de ponction (1000) dotée d'un couvercle de double protection comprend une aiguille de ponction (200) et un élément manchon (100), lequel comprend une canule creuse (130), laquelle comprend une extrémité distale (132) et une ouverture (131) de manchon. L'aiguille de ponction (200) comprend une partie de préhension (202) et une partie d'extrémité distale (206) ainsi qu'une partie tige intermédiaire (204). Lors de l'utilisation de l'instrument de ponction (1000), l'aiguille de ponction (200) pénètre l'élément manchon (100) destiné à pénétrer le corps d'une
