The invention belongs to the field of daily necessities, in particular to a thermos bottle capable of preventing the falling of a bottle stopper, which comprises a casing, wherein the casing is provided with a liner, the lower end of the casing is screwed with a base, and the lower end of the inner casing in contact to the upper end of the base, the base is provided with a cavity, the inner side wall of the cavity is fixedly connected with an annular elastic airbag, and the cavity is provided with a freely movable balancing weight, the upper end of the liner is provided with a bottle stopper,the upper end of the bottle stopper is fixedly connected with a fixing block, the upper end of the fixing block is fixedly connected with a handle, and the upper edge of the casing is fixedly connected with a C-shaped curved airbag, the curved airbag is in communication with the annular elastic airbag through a connecting pipe, the upper end of the fixing block is provided with an arc-shaped limiting slot matched with the curved airbag, and a handle is fixedly connected to the side wall of the casing. The thermos bottle capable of preventing the falling of a bottle stopper can utilize the pressing of the balancing weight to enable the C-shaped curved airbag to clamp the bottle stopper to prevent the bottle stopper from falling.