The invention relates to a method for low-pressure casting thin-wall long-sized castings and equipment used by the same, wherein metal materials are firstly smelted, a furnace body is closed, a mould is prepared, dry compressed air is filled into an airtight container, under the action of gas pressure, liquid metal rises along a multitube and multi-sprue riser tube and stably enters a mould cavity through a sprue, and the gas pressure on the liquid level in a crucible is kept; and after the casting is completely solidified, the gas pressure on the liquid level is relieved to enable the unsolidified liquid metal in the riser tube to flow back into the crucible, and then the casting is taken out. The method for producing the thin-wall long-sized casting has the advantages that mold-filling is stable, a product is well molded, the mold-filling of liquid metal is carried out under the pressure, the liquid metal has good liquidity and is convenient to cast the thin-wall casting of the kind the casting is crystallized and solidified under the pressure and has a compact structure, so the mechanical property is improved, a pouring system is simple, casting heads are reduced, mechanization and automation are realized, the labor intensity of workers is reduced, a mould with multi-cavities is realized, the production efficiency is improved and the like.