Abstract: Objectives To investigate the implosion response characteristics and protective effects of deep-sea composite pressure-resistant spheres under various conditions. Methods Firstly, based on deep-sea composite pressure-resistant structures, the Arbitrary Lagrangian-Eulerian method was employed to simulate the implosion fluid-structure interaction process. Subsequently, the effectiveness of the numerical method was verified by comparing the results with those from typical underwater implosion experiments. Finally, a parametric discussion was conducted to provide a more comprehensive understanding of the implosion response characteristics of the composite pressure-resistant structure. Numerical studies of the implosion of composite pressure-resistant structures under different working depths, implosion trigger directions, and numbers of implosion triggers were carried out, and their influence patterns were analyzed. The influence of the pressure-resistant structure wall thickness on the external conditions was also studied. The similarities and differences in the effects of different factors on the response characteristics of ceramic structures and composite structures were compared. Results Working depth significantly impacts the implosion response characteristics of composite pressure-resistant structures. As the working depth decreases, the intensity of the structural response and the peak value of the flow field pressure are notably weakened. For the pressure monitoring point located at a distance of one radius from the center of the sphere, the peak values were reduced by 63.3% and 71.7%, respectively。For structures with a relatively thin total wall thickness, the degree of this weakening will decrease accordingly. The implosion trigger direction and the number of implosion triggers have an insignificant effect on the implosion response of the composite pressure-resistant structure. Conclusions This study reveals the implosion response characteristics of deep-sea composite pressure-resistant structures under different external conditions. The research results provide valuable references for the design of underwater implosion protection and engineering applications.