Spaced armor has a simple structure and is easily produced with low cost. Previous authors calculated how a jet penetrates spaced armor; but, this study provides both a theoretical calculation method describing the interaction of a jet with spaced armor and experimental data which agree well with the theoretical values. The effects of several factors were explored using LS-DYNA such as the distance between the first plate and the second plate as well as layer thickness on the interaction between the jet and the target. A method for simulating the protection afforded by spaced armor and supporting the design of spaced armor is presented.