The invention discloses an assembling and disassembling device of a calorimetric cover used in explosion heat measurement. The device is mainly composed of the parts of a calorimetric cover, a bottom plate, a guiding column, a lever support, a guide rail, a slide block, a limiting column, a counterweight, a counterweight shaft, a lever, a lever shaft, a curved plate, a steel wire rope, a lifting lug, a main power mechanism, and the like. The device has no cantilever beam structure. A calorimetric cover assembling position is accurate. Lifting, lowering, and deviating operations of the calorimetric cover are effort-saving and convenient, such that requirements are satisfied. Force is applied on the calorimetric cover through a suspension ring, such that the forces on various parts of the calorimetric cover are balanced, a calorimetric cover structure deformation problem caused by unbalanced force is avoided, and thus a defect of the failure of normal assembling of the calorimetric cover is avoided. With a horizontal-moving limiting method, assembling difficulty of the calorimetric cover is prevented, and bruising caused by misalignment of a temperature sensor on the calorimetric cover and a sensor hole on a heat preservation tank is avoided. Therefore, the positioned assembly of the calorimetric cover can be carried out accurately and conveniently.