The invention discloses a high-energy dynamite charging thermal expansivity measuring device and method. The problem that an existing test device fails to measure solid state dynamite charging thermal expansion characteristic parameters is solved. According to the basic principle of the device and method, a heating jacket is used for heating dynamite charging to a certain temperature, a thermocouple is used for measuring a dynamite temperature in real time, spring steel with a known deformation coefficient is used for measuring pressure generated when the dynamite charging is heated and expanded, meanwhile, deformation of the spring steel is used for pushing a displacement sensor located above to obtain displacement data, and thus, a three-dimensional relational graph of the temperature, the expansibility and the expansion size of the dynamite charging is established. The device and method provided by the invention have the advantages of high universality, high accuracy and low cost, the requirements for measuring expansion parameters of liquid explosives, slurry explosives and all-solid-state explosives can be met simultaneously, and a more comprehensive data support is provided for middle-large sized ammunition charging designs.