Floating type manufacturing method of immersed pipe section externally covered with steel housing

The invention discloses a floating type manufacturing method of an immersed pipe section externally covered with a steel housing. The method comprises the following steps: processing a steel plate into an U shape, wherein reinforcing ribs, rivets and temporary supports are welded at the inner side of the steel plate; binding reinforcing steel bars in the U-shaped steel plate; pouring full-section concrete within 3-4m around two ends of the steel plate, and pouring concrete of a bottom plate at the rest part, all middle walls and 3-4m lower sidewalls; mounting steel end housings, steel end sealing walls and guide devices at two ends; then sliding the pipe section into water; conveying to an outfitting quay in a floating manner, and pouring the rest reinforced concrete in a floating state; outfitting for the second time; and conveying the pipe section to an assigned position in a floating manner, and immersing. The method is free of excavation of a large foundation pit, needs a small area, and is small in dredg