The invention discloses a manufacturing method of aerated concrete blocks internally provided with cavities. The manufacturing method is mainly used for aerated concrete block manufacturing, specifically, before aerated concrete blank bodies are poured, a plurality of vertical air-filled film rods are installed in a mould; and after the aerated concrete blank bodies are poured, maintained and cut, the multiple vertical cavities are formed in each single aerated concrete block, so that the weight of the blocks are reduced, and carrying and construction both are quite convenient. The main manufacturing method of the aerated concrete blocks comprises the steps that the multiple air-filled film rods are connected in series by strings to form a set of air-filled film rod sets; the strings at one end of each air-filled film rod set is hung on a hook of a bottom plate of the lower end of the mould, and the strings at the other end of the air-filled film rod set is hung on a hook of the lower end of a supporting rod; the multiple sets of the air-filled film rod sets are installed; after the aerated concrete blank bodies are cut into the single aerated concrete blocks, the multiple vertical cavities are formed in each aerated concrete block; and then the aerated concrete blocks are manufactured according to an existing technical method.