The dynamic finite element method was applied to simulate the explosive flow field of an axisymmetric cylindricblastchamberwith an ellipsoid cap, the stress and strain responses of the steel-concrete part were analyzed. The numerical simulationresultsshowthat the major low and high frequency of stress wave of steel liner is generated by reduplicate reflection of the blastwave on steellinerand intrinsic vibration of liner structure, and that the twice reflection of the blast wave on cap part of thechamber is important,thereby the space-time distribution of plasticity and damageresponses of concrete have been fundamentallyaffected.Thenumericalresults are in good agreement with experimental results.