The invention provides an eccentric spiral powder spreader and a processing method thereof. The powder spreader comprises a machine rack, a powder discharge cylinder, a powder hopper and a spiral rod. The powder discharge cylinder is fixed on and horizontally and transversely arranged on the machine rack, and at least one row of powder discharge holes are formed in the lower side wall of the powder discharge cylinder in the horizontal direction; the powder hopper is arranged above one end of the powder discharge cylinder and is communicated with the upper side wall of the powder discharge cylinder to make disinfection powder in the powder hopper fall into the powder discharge cylinder by relying on gravity; the spiral rod penetrates through the powder discharge cylinder horizontally and transversely, and the central axis of the spiral rod is located below the central axis of the powder discharge cylinder and is parallel to the central axis of the powder discharge cylinder, wherein the spiral rod is provided with a near end thread, a middle part thread and a far end thread, the near end thread is adjacent to the powder hopper and is a dual right-hand thread, the middle part thread is a single right-hand thread, the far end thread is a dual right-hand left-hand thread, and the height of the left-hand thread is larger than that of the right-hand thread. The powder spreader is convenient to operate, can be applicable to all silkworm breeding application occasions, and is high in powder spreading efficiency and environmentally friendly.