The invention discloses a prepuce cutting suture device achieving full cutting. The problem is solved that local parts of the glans penis are connected and are not cut off after prepuce cutting. According to the technical scheme, a movable disc is movably arranged in a knife housing, a movable rod can penetrate through the movable disc, an annular cutting knife and a suturing nail are positioned on the movable disc, an annular groove is formed in the movable disc, a track groove is formed in the groove wall of the annular groove and extends in the peripheral direction of the annular groove, two ends of the track groove are vertically staggered, a boss capable of moving in the annular groove is arranged on the annular cutting knife, a sliding block clamped with the track groove is connectedto the boss, the sliding block is located at the end, close to a glans penis cap, of the track groove in an initial state, and the sliding block moves to the other end of the track groove along the track groove, so that the annular cutting knife also rotates while cutting the prepuce.