The invention discloses a manual low-cost casting method of a large aluminum alloy shell. The manual low-cost casting method comprises the steps of processing a wood former, putting the wood former with an upward plane and a downward inner cavity in a frame, filling a mold with resin sand as a lower sand mold, and putting frozen iron at the wall thickness of the mold and chilled sand at the chamfering; putting a top gating system on an upper sand mold, wherein a riser is located in the large thick position of the upper sand mold, and uniformly drilling a plurality of air outlet holes in the top of the upper sand mold; filling the wood former with resin sand, pre-burying an air outlet rope and a hook, and putting frozen iron at the wall thickness; heating Al to 730 to 740 DEG C, adding Cu,insulating for 9 to 11 min, then heating to 750 to 760 DEG C, adding Mn, insulating for 5 to 8 min, finally, cooling to 740 to 750 DEG C, adding Ti, deslagging and introducing argon to degas for 13 to17 min, so that molten aluminum alloy is obtained; and matching a casting mold with a sand core, assembling the mold, and then cooling after the molten aluminum alloy is poured in through a pouring cup. The manual low-cost casting method has the characteristics of low cost, simple tool and high qualified rate.