In order to improve the high level tank armor protection ability, the ANSYS/LS-DYNA finite element software was used to numerically simulate the process of shaped charge jet penetrating liquid composite armor of cell structure. The effects of the different cell structure heights and composite armor angles on the anti-jet penetration property of liquid composite armor of cell structure were analyzed, the influence of the internal liquid’s radial convergence and splash on the jet’s stability and deformation of the panel and back panel were studied; the reliability of the simulation method was validated by residual depth penetration experiments of a jet vertically penetrating liquid composite armor. The results show that the composite armor internal liquid’s radial convergence and splash will influence the stability of the jet and reduce the residual penetration ability. Increasing cell height and the composite armor dip can reduce the stability of jet and effectively improve the protective performance of liquid composite armor.