A numerical simulation test of the internal explosive loading on largespace structure was carried out by employing algorithm ANSYS/LSDYNA.An appropriate model was established for calculating the dynamic responses of the largespace cylindrical reticulated shell under innerblast loading based on the proof of correctness and reliability of the model and parameters selection.Combining the Ritz vibration mode superposition method with the Proper Orthogonal Decomposition (POD) method, the problems of spatiotemporal asynchrony of shock waveforms and pressure distributions on largespace structure surface were solved and the calculation for dynamic response of largespace structure was reduced and simplified.Furthermore, the numerical simulation of dynamic responses was carried out.And the influence of the ratio of rise to span and the explosive position on the dynamic responses of the structure was studied.It was found that the calculation model was suitable for the dynamic response analysis of the largespace cylindrical reticulated shell under internal explosion and the cylindrical reticulated shells with bigger ratios of rise to span were stronger in the capacity of antiexplosion.In general, the damages to the largespace structure caused by eccentric blast shock waves were more serious than that caused by central explosion.And it was the most disadvantageous to the edge components of the structure.The more attention should be paid to the antiexplosion capacity of the support areas and the edge components while designing the shells.