To investigate the stress wave effect in semi-infinite concrete targets under penetration-implosion loadings induced by reactive jet （RJ）， two sets of RJ peneration-implosion experiments were conducted to obtain stress wave data and characteristic damage patterns of concrete targets. LS-DYNA software combined with a restart algorithm was used for staged numerical simulations of the penetration-implosion process， and to analyze the stress wave propagation characteristics in concrete under the combined action of RJ penetration and explosion. The findings demonstrate that numerical and experimental results showed good agreement in stress waves and target damage features. During the penetration stage of RJ， concrete failure occurs after successive loadings of dynamic stress wave zone and static high-pressure zone， with the latter having a faster loading rate but a shorter action duration. The concrete damage caused by RJ penetration accelerates energy dissipation， reduces peak stress during the explosion stage， but accelerates stress wave propagation. Compared with the undamaged target， the peak stress of the explosion in the target after RJ penetration decreased by up to 47%， and the growth rate of the stress wave propagation speed could reache up to 7%. However， when the depth of measuring point exceeds 335 mm， the influence of RJ penetration on the explosion stage can be ignored.