The diving body is a special structure of the small water area twin hull (SWATH). To solve the local strength assessment of the diving body, the finite element models of the diving body were built. Then the design loads was calculated according to the rules and regulations for the classification of special service craft. The typical three-cargo-holds models in the diving body was calculated and analyzed. The results show the stress of the target cabin in the bow and stern of diving body is larger than the middle. The stress of the target cabin under damaged conditions is larger than healthy conditions. And the stress of the transverse frame, transverse bulkhead, longitudinal girder, stiffeners in the diving body are larger than other area. These problems should be focused when the diving body was designed and built.