Cup body of vacuum cup

The utility model discloses a cup body of a vacuum cup, which can improve the thermal insulation performance of the vacuum cup again on the basis of the thermal insulation performance of the existing vacuumizing process. Comprising an inner container and a shell which are in sealed connection at an upper end opening part, a sealed interlayer defined by the inner container and the shell is a vacuum layer, the inner container is provided with an inner container opening part and an inner container main body from top to bottom, and in the axial outward direction, the heat flow of the inner container opening part is smaller than that of the inner container main body; when heat of hot water in the water cup is conducted to the inner container opening part through the inner container body in the axial direction, due to the fact that the heat flow of the inner container opening part becomes small, heat resistance can be increased, outward transfer of heat through the inner container opening part can be slowed down, a