With the increasing damage ability of anti-ship weapons to naval ships, the box-girder structure has been widely recognized and concerned as a new type of anti-explosion structure.The numerical simulation method is used to calculate the structural deformation, acceleration and structural energy absorption under the explosion load in the cabin. Considering the influence of the structural weight change, the weight response index is introduced to evaluate and analyze the effect of improving the ship's damage resistance.The research shows that: under the premise of reasonable plate thickness, the damage resistance of the box-girder structure to the dangerous section of the ship can be significantly improved, and the improvement effect is related to the tonnage and the hull structure of the ship, which provides the surface naval ship with the box-girder structure design.