The structural analysis of the Ro-Ro access demands further investigation due to its complexity and the applicability problems in the requirements of the vehicle deck size of the China Classification Society Rules for Classification of Sea-going Steel Ships. The plate, beam structure and primary supporting members of the Ro-Ro access are studied to establish the descriptive requirements of the vehicle deck plate thickness and the stiffener scantlings by using the theoretical formula derivation and the numerical fitting method. At the same time, the direct calculation requirements for the primary supporting members of the access that meet the unified requirements of the International Association of Classification Societies (IACS) and cover all kinds of loads are formed and then verified through case calculations. The results show that the optimized descriptive requirements and direct calculation requirements have good applicability. This study is of great significance for improving the safety and lightweight level of the Ro-Ro access structure design.