The present invention relates to the field of thermal insulation devices, and particularly to a foldable thermal insulation case. It includes a case body, a case lid covered on the case body and a liner provided inside the case body. The liner includes a bottom plate corresponding to a bottom wall of the case body and side plates corresponding one to one to sidewalls of the case body. There are a collapsed state and an unfolded state for the liner. When the liner is in the unfolded state, each of the side plates stays upright around the bottom plate and is jointed with the bottom plate； in this way, the individual side plates and the bottom plate support the case body, and the case body is unfolded. When the liner is converted from the unfolded state into the collapsed state, that is, the side plates are bent downwards with respect to the bottom plate and stacked on the bottom plate, the case body may be folded downwards, and the size of the thermal insulation case is reduced after the case body is folded. Therefore, the invention enables the thermal insulation case to be folded, and the size of the thermal insulation case to be reduced effectively.
