The invention relates to a shell positioning and pressure-maintaining heating device. The shell positioning and pressure-maintaining heating device comprises a first heating mat and a second heating mat, wherein the first heating mat is arranged on a first driving mechanism and the second heating mat is arranged on a second driving mechanism. The shell positioning and pressure-maintaining heating device is characterized in that the first heating mat is parallel to the second heating mat, the first driving mechanism is of a vertical gate type structure, and the second driving mechanism is horizontally arranged below the first driving mechanism. Vertical movement is guaranteed due to the gate type structure of the first driving mechanism, in this way, the inner surface and the outer surface of a shell can be clamped by the two heating mats, and pressure-maintaining heating is further achieved. The pressure-maintaining heating device is provided with the upper heating mat and the lower heating mat so that the shell can be stably heated for a long time. Meanwhile, due to the facts that the heating area is large and the upper surface and the lower surface are heated at the same time, it is guaranteed that the heat temperature fluctuation is small, i.e., the heating temperature is controllable and ranges from the room temperature to 400 DEG C, and the heat temperature fluctuation is +/- 1 DEG C.