The invention discloses a method and a device for the continuous preparation of high-purity silicone hydride gas, relating to the technical field of preparation method and device of chemical materials; the preparation method comprises the following steps: alkoxy silane or trichlorosilane is subjected to a disproportionating reaction to produce the silicone hydride gas under an anaerobic conditionand an action of a catalyst by a gas generating unit, a low-temperature fractionation unit and a profound hypothermia liquefying unit; and the silicone hydride gas goes through a two-stage low-temperature fractionation process to obtain purity meeting the electron level requirement. The device integrates the generation, two-stage purification, liquefaction and re-gasification of the silicone hydride gas in one system so that the produced silicone hydride gas can be directly introduced into the production line (for the preparation of polysilicon and thin-film solar cell as well as other applications) or canned.