The structural strength of jack-up units is the key issues in the design of ship and ocean engineering structures. Based on ABS MODU, the yield strength of CJ46 self-elevating drilling platform main hull structure is checked. Firstly, the environmental loads (wind, wave and flow) in three loading conditions which are required by specification are calculated by using GeniE (DNV). Then the 3D finite element model of main hull structure is established. The yield strength is checked and the results shown the large stress areas are leg well, jackcase which is connected with the leg and bulkhead which is main support structure under the cantilever sliding device, while the results meet the requirements of ABS MODU. Finally, the influence of the openings located in main longitudinal bulkheads are evaluated, meanwhile the main longitudinal bulkheads under skidding box need particular concern.Copyright © 2015 by ASME