Abstract: Non-contact underwater explosion can generate violent movement on hull girders, which may cause longitudinal strength problems. The explosion bending moment can be calculated using a detailed finite element ship model, but this costs considerable working time. This paper advances a new method for calculating explosion bending moment by a hull girder model. The explosion bending moment of typical ship sections is calculated according to a detailed ship model and simplified hull girder model using ABAQUS software. Comparisons between the results indicate that the simplified hull girder model is easily created and has good precision, enabling it to provide a reference for the estimation of explosion bending moment in hull girders subjected to non-contact underwater explosion.