In order to understand the solidification process of casting explosive, the temperature fields of RHT explosive during solidification process were simulated by finite element method. The shrinkage of RHT explosive after solidification was also predicted. The results show that the temperature difference between inner and outer of RHT explosive during solidification process is quite great. There exists an inflexion on the temperature curves in the centre area. And the porosity will be presented on the middle position of solidified RHT explosive. On the other hand, the temperature of RHT explosive during solidification process was also tested by thermocouple and the interior quality was inspected by ICT, and the simulated results and tested results were also compared. The results show that the finite element method can be used to simulate the RHT explosive solidification process.