To better understand the thermal decomposition behavior of energetic materials， recent advances in key theoretical methods and experimental techniques， including quantum chemical calculations， molecular dynamics simulations， coupled thermal analysis techniques， and spectroscopic and structural characterization methods were summarized. The capabilities and limitations of these approaches in identification of reaction pathways and characterization of energy release and structural evolution were discussed. Quantum chemical calculations provide detailed insights into potential energy surfaces and initial bond cleavage process， but due to the limitations of computational scale， they are primarily applicable to the small molecular systems. Molecular dynamics simulations enable tracking of atomic motion and energy transfer， making them suitable for analyzing typical decomposition pathways， but with limited time scales. Coupled thermal analysis techniques allow simultaneous characterization of thermal effects and gaseous products but have limited ability to identify transient intermediates. Spectroscopic and structural characterization methods can probe the processes of phase transitions， bond rearrangements， and valence state evolution， yet their resolution often hampers the observation of rapid structural changes. Based on the comparative analysis of different techniques， future studies should emphasize integrating theoretical simulations with in situ high-resolution diagnostics， combined with machine-learning potentials， high-throughput computation， and multiscale modeling to promote the research on the thermal decomposition mechanism of energetic materials towards multi-scale coupling and predictable modeling， and enhance the ability of characterization and prediction of complex thermal decomposition behaviors.