Abstract: In order to analyze the combined damage effects of reactive material jet penetration and blast, the change of blast effect during reactive material jet penetration was studied by combining experimental research and theoretical analysis. Vented chamber calorimetry (VCC) experiments were carried out to investigate the characteristics of implosion overpressure after the reaction material jet penetrated steel targets of different thicknesses, and the influence of the thickness of the penetration target plate on the penetration morphology of the reaction material jet and the peak value of the implosion overpressure was analyzed. Based on the virtual origin theory, a micro-element model was developed to describe the process of reactive material jet explosion. The results show that the overpressure formed by the reaction material jet in the tank has the characteristics of large peak value, long action time and uniform spatial distribution, and there is an incomplete reaction part in the forming reaction material jet. The density attenuation of the reactive material jet greatly increases the mass of the jet consumed by the subsequent jet penetrating per unit length, resulting in a parabolic attenuation of the implosion overpressure peak with increasing penetration depth. The model can be used to describe the relationship between the blast effect and the penetration depth when the reactive material jet impacts the target, which provides help for analyzing the damage mechanism of the reactive material jet.