As for the recent structural design of a ship, direct strength calculations are approved in classification society's rules, and wave loads for the calculation are given. However, such wave loads may be taken on the premise that the buckling or collapse strength of a ship will be checked by the direct strength calculation. In consequence, it may be questionable to apply such wave loads to the investigation of fatigue strength of a ship. In fatigue analysis of a ship, it is most important to estimate accurate pressure fluctuations in time and space. With the use of the pressure fluctuations, the stress fluctuation can be calculated. In the present paper, the fluctuation in time and space of pressures acting on a bulk carrier in waves were investigated. Time histories of the pressure along ship's hull were calculated by Boundary Element Method. Surveying the pressures, distribution patterns along the ship's hull of the pressure fluctuation were classified ; 4 typical patterns of pressure distribution were introduced. With the use of these pressure distributions, structural analyses were performed for 1/2 hold spans fore and aft part of a bulkhead in port side of the ship by Finite Element Method. The stress distributions on the inner bottom plate and the bilge hopper tank plate were investigated. Finally, design loads for fatigue analysis of a large ship are discussed.