Abstract: A simulation program for explosive ignition and detonation after cook-off was developed. The combustion solver was calculated by alternating direction implicit scheme, and the detonation solver was calculated by fifth-order WENO scheme. The numerical simulation of the whole process from ignition response to detonation evolution was realized. The alternating direction implicit scheme used was characterized by unconditional stability, low grid constraint and high solving efficiency. The phase transformation of explosive was described by using liquid fraction β. The numerical simulation of initiation after cook-off of TNT was performed, by which the local temperature evolution and critical ignition threshold of explosive as well as the influence of phase transformation on the cook-off process were revealed. In the meantime, TNT cook-off experiment was carried out, and the program was verified by embedded thermocouple sensor. The simulated temperature rise curve and phase change platform coincided well with the experimental results, which validates the reliability of the calculation. The ignition region and evolution law of the heated explosive were revealed by simulation of mechanical-thermal-chemical coupling. It is found that temperature dominates the initial stage of reaction, and pressure dominates as reaction develops.