Abstract: To simulate the shock initiation of the multi-component PBX explosive under different explosive component ratios, with the consideration of coupling mechanism between the explosive components in a multi-component PBX explosive, a new pore collapse hot-spot ignition model is proposed in this paper based on an elastic/viscoplastic double hollow sphere pore collapse model. A new theoretical expression of hot-spot reaction rate was obtained according to this model. Moreover, by using this model, the reaction degree of HMX/TATB binary-component PBX explosives under different explosive component ratios in the ignition stage of shock initiation was numerical calculated. The numerical results show that the model can well describe the influences of the explosive component ratios on the ignition process of shocked multi-component PBX explosives.