The invention discloses a top outer shell of a pulse generator. The top outer shell of the pulse generator comprises a lifting rod (1), a rubber cup (2), a first outer shell body (3), a guide sleeve (4), an oil seal device (6), a second outer shell body (7), a push rod (8) and a piston assembly (9). The rubber cup (2) is arranged on the first outer shell body (3). The lifting rod (1) is arranged in the rubber cup (2). The guide sleeve (4) is arranged on the lifting rod (1). The oil seal device (6) is arranged at an end of the second outer shell body (7). The piston assembly (9) is arranged inside the second outer shell body (7). The push rod (8) is arranged on the piston assembly (9). The first outer shell body (3) and the second outer shell body (7) are detachably connected. The lifting rod (1) and the push rod (8) are detachably connected. The top outer shell includes the first outer shell body and the second outer shell body overall through the design, only the first outer shell body needs to be detached down and replaced when the rubber cup is damaged, so that the repair cost is lowered, and the service life of a whole device is prolonged. The structure is simple.