The invention relates to a waterproof method for a roof pipe of a metal roof plate. The waterproof method comprises the steps that first, a waterproof cover piece for a sealing hole is made, the waterproof cover piece for the sealing hole includes a waterproof cover sheet and an aluminum sheet located at the lower part of the waterproof cover piece, the waterproof cover piece is made of rubber, the bottom of the rubber part of the waterproof cover piece is a cylinder, the upper part of the same is cone-shaped and an opening is formed in the cone-shaped part, and the diameter of the opening issmaller than the diameter of a pipe; second, the outer surface of the roof pipe is cleaned without oil pollution; third, the waterproof cover piece for the sealing hole is embedded into the pipe in asleeving mode, and the opening of the waterproof cover piece for the sealing hole is ensured to be upward and embedded tightly into the pipe in a sleeving mode; and fourth, a neutral sealant is coatedat the lower part of the aluminum sheet of the waterproof cover piece of the sealing hole and smeared evenly, the waterproof cover piece of the sealing hole is pressed against the metal roof plate, and the aluminum sheet and the metal roof plate are fastened with tapping screws. According to the waterproof method for the roof pipe of the metal roof plate, the waterproof effect is enhanced, and the waterproof material of waterproof pitch points of the roof pipe is improved, so as to improve the waterproof construction efficiency and the waterproof effect.