In this study, all-atom MD simulations were carried out to investigate the temperatureinduced phase transition in (BA) 2 (MA)Pb 2 I 7 . Our simulations predicted the transition from a triclinic phase at lower temperatures to a tetragonal phase at higher temperatures, with the predicted structures closely aligning with those measured in experiments. The critical phase transition temperature predicted by our simulations is lower than that observed ex-perimentally. Further work is certainly required to enhance the accuracy of the empirical force field, possibly through re-parametrization of the force field parameters or the use of machine learning potentials. Nevertheless, many predictions from our simulations are supported by existing experimental data. Some of these predictions are qualitative, while others also demonstrate quantitative agreement. Beyond the order-disorder phase transition mechanism, our study uncovers the phenomena and atomic-level mechanisms contributing to the phase transition, summarized as follows.