An airtight sheath for packing a bottle, the airtight sheath made of at least two outer films heat-sealed together and comprising: a first buffering unit comprising a plurality of first air columns , and two distal heat-sealing sides being heat-sealed to terminate two opposite sides of the first buffering unit; a second buffering unit comprising a plurality of second air columns , two opposite sides of the second buffering unit being heat-sealed with the two distal heat-sealing sides of the first buffering unit; a bottom unit comprising a plurality of bottom air columns connected with ends of the plurality of first air columns and second air columns , whereby a packing space is formed by the first and second buffering units and the bottom unit and is open at a top of the sheath for packing a bottle therein, so that the bottom unit and the first and second buffering units cooperatively forming a packing space for packing the bottle therein; and a cover extending from one end of the first buffering unit opposite to the bottom unit and disposed in the packing space , the cover comprising two connecting air columns and at least a lid air column located between the two connecting air columns , each of the connecting air columns and the lid air column respectively having a top portion and a shielding portion bending from the top portion and extending downward to the packing space , the top portion extending and bending from the first air column , a side of each of the connecting air columns opposite to the lid air column being heat-sealed with the first buffering unit , whereby the cover and the first buffering unit cooperatively forming an insertion slot communicating with the packing space for enveloping a neck portion of the bottle . a first buffering unit comprising a plurality of first air columns , and two distal heat-sealing sides being heat-sealed to terminate two opposite sides of the first buffering unit; a second buffering unit comprising a plurality of second air columns , two opposite sides of the second buffering unit being heat-sealed with the two distal heat-sealing sides of the first buffering unit; a bottom unit comprising a plurality of bottom air columns connected with ends of the plurality of first air columns and second air columns , whereby a packing space is formed by the first and second buffering units and the bottom unit and is open at a top of the sheath for packing a bottle therein, so that the bottom unit and the first and second buffering units cooperatively forming a packing space for packing the bottle therein; and a cover extending from one end of the first buffering unit opposite to the bottom unit and disposed in the packing space , the cover comprising two connecting air columns and at least a lid air column located between the two connecting air columns , each of the connecting air columns and the lid air column respectively having a top portion and a shielding portion bending from the top portion and extending downward to the packing space , the top portion extending and bending from the first air column , a side of each of the connecting air columns opposite to the lid air column being heat-sealed with the first buffering unit , whereby the cover and the first buffering unit cooperatively forming an insertion slot communicating with the packing space for enveloping a neck portion of the bottle . <EOS>