The invention discloses a preparation technology of a high-strength aluminum alloy precision casting board and relates to the technical field of material machining. According to the technology, on thebasis of the original technology, the technology is optimized, the steps of solid-solution quenching, three-level stretching and double-stage aging heat treatment and reasonable step technology parameters are introduced, the new technology mainly comprising dosing, smelting, casting, homogenizing treatment, machining treatment, solid solution quenching, three-stage stretching, double-stage agingheat treatment and machining treatment is formed, the problem that when an existing technology is used, stress in the aluminum alloy precise casting board is released incompletely, machining deformation is generated, and the strength is insufficient, and by means of the technology, the high-strength aluminum alloy precision casting board which is not prone to machining deformation and high in strength can be obtained.