The invention relates to a middle slurry-permeating type single-bag grouting hole sealing device and a hole sealing method thereof. The middle slurry-permeating type single-bag grouting hole sealing device comprises a recyclable grouting pipe, a grouting pipe joint, a front gas extracting pipe, a rear gas extracting pipe, a flow guiding device, a dual-hole pipe, a pressure control valve, an expansion bushing and an expansion bag, wherein the recyclable grouting pipe is communicated with a grouting channel of the flow guiding device, the front gas extracting pipe is sleeved by the hole sealing device through the flow guiding device in the use process, the hole sealing device is grouted through the recyclable grouting pipe, and the expansion bushing and the expansion bag expand after being filled with slurry so as to block drill holes. According to the middle slurry-permeating type single-bag grouting hole sealing device, the relatively effective grouting hole sealing of the drill holes in a hole sealing segment can be realized, and the formation and the development of air-leaking fractures in the periphery of the drill holes of the hole sealing segment can be well prevented. By virtue of the hole sealing method of the middle slurry-permeating type single-bag grouting hole sealing device, high stress regions are formed on the periphery of the drill holes of the hole sealing segment, so that the air permeability of mediums on the periphery of the drill holes of the hole sealing segment is reduced, and the effective grouting hole sealing of the drill holes of the hole sealing segment is realized.