Abstract: A thermos having multiple hermetical heat preservation structures and a glass liner easy to disassemble and assemble. The thermos includes a bottle cap, a fixing cap, a water seal piece, a seal ring, the glass liner and a bottle body, wherein when the bottle body and the bottle cap are connected in a matching manner, the water seal piece and a bottle opening of the glass liner are matched hermetically. By the above solution, the thermos has the characteristics of good airtightness, improved heat preservation property, and high durability and reliability.