The invention discloses a roof construction method of a broken bridge waterproof roof gutter spout funnel. The roof construction method includes the following steps that a water stop ring on an outerbarrel of the gutter spout funnel is pre-embedded in a concrete layer when a roof reinforced concrete floor slab is poured; a first leveling layer, a vapor barrier layer, a heat insulating layer, a slope making layer and a second leveling layer are laid successively on the concrete layer; a coiled material layer is laid on the second leveling layer, the tail end of the coiled material layer is putinto a water stop groove of the outer barrel, and then the water stop groove is filled with waterproof glue; a waterproof layer and a coiled material protective layer are laid successively on the coiled material layer; and the gutter spout funnel is inserted into the outer barrel pre-embedded in the concrete layer through an inner barrel. According to the roof construction method of the broken bridge waterproof roof gutter spout funnel, the waterproof effect is good.