This study presents numerical simulation on soil pressure due to underground explosion. Previous tests examined that effects of water content and damping with distance were important characteristics of the soil pressure due to underground explosion. A few numerical studies attempted to reproduce the chacteristics of the soil pressure using several soil material models, and there are still many technical issues on modeling soils and procedure of determining analytical constants. This study proposed a reasonable engineering model of the soil pressure due to underground explosion based on a parametric study. The proposed model was validated as compared with past test data.