In order to strengthen the structural strength of hull block with large-opening flat cavity structure, a finite element model is established combined with the structural characteristics, lifting lug arrangement, and hoisting assembly strengthening scheme of hull block, and the block hoisting assembly is simulated with the numerical simulation to analyze the structural deformation of deck and lifting lug area. The optimization of hoisting assembly strengthening scheme is performed according to the forecast results, which can provide certain guidance for the optimization of hoisting assembly strengthening scheme of subsequent similar structures.