The thermal stability of a dehydrated Cu₃(BTC)₂ (copper(II) benzene 1,3,5-tricarboxylate) metal–organic framework was studied by molecular dynamics simulation with a ReaxFF reactive force field. The results show that Cu₃(BTC)₂ is thermally stable up to 565 K. When the temperature increases between 600 K and 700 K, the framework starts to partially collapse. The RDF analysis shows that the long range correlations between Cu dimers disappear, indicating the loss of the main channels of Cu₃(BTC)₂. When the temperature is above 800 K, we find the decomposition of the Cu₃(BTC)₂ framework. CO is the major product, and we also observe the release of CO₂, O₂, 1,3,5-benzenetricarboxylate (C₆H₃(CO₂)₃, BTC) and glassy carbon. The Cu dimer is stable up to 1100 K, but we find the formation of new copper oxide clusters at 1100 K. These results are consistent with experimental findings, and provide valuable information for future theoretical investigations of Cu₃(BTC)₂ and its application in adsorption, separation and catalytic processes.