In order to investigate the heat transfer behavior and thermal safety characteristics of energetic charge modules with complex structures under thermal environments, a two-dimensional transient thermo-chemical coupled cook-off model was established. A one-step reaction mechanism of the combustible cartridge and porous propellant was coupled in the model. Cook-off experiments of energetic materials were conducted to validate the proposed model. The calculated ignition delay times and ignition temperatures were in good agreement with the experimental results, which confirms the accuracy of the model. On this basis, the cook-off response of the energetic charge module under different heating rates is numerically investigated. The results show that heat transfer from the external thermal environment and heat released by exothermic reactions of energetic materials jointly promote the occurrence of cook-off. As the heating time increases, the temperature of the porous propellant inside the energetic charge module gradually rises, and the exothermic reaction is significantly intensified with increasing temperature, releasing more reaction heat simultaneously. Heat is progressively accumulated inside the energetic charge module, and cook-off is ultimately triggered under high thermal load conditions. It is concluded that, with increasing heating rate, the cook-off response region evolves from a single axially symmetric ring structure to two symmetrically distributed ring-shaped regions. The center of the response region gradually shifts upward and outward along the diagonal direction of the charge, exhibiting an outward expansion trend. Under fast cook-off conditions, the response region migrates to the propellant region near the inner-wall corner of the combustible cartridge. Under fast (7.2 K/min), intermediate (5.4 K/h), and slow (2.2 K/h) heating conditions, the ignition temperature of the energetic charge module ranges from 460.0 K to 462.6 K.