This article, basing on the field test stress of an oil-storage tank in the site, investigated finite element modeling method for large oil storage tanks. To study the effects of contact conditions among the tank wall, bottom plate and the foundation, the soil of the foundation, and holing on the tank stress, six different finite element models were built by ANSYS finite element analysis software. The stresses in the tank were calculated under the gravity load and the water pressure. Results of the six models have been compared with the field test values. It was obtained for the stress distribution in the tank wall, bottom plate, and big horn weld and around the manhole from which the influence scope and extent to the tank was investigated. It shows that the calculated stresses have a good agreement with measurement. The plane model has enough precision for the tank stress analysis. The contact conditions and soil affect on the stress in the scope with 0.2H and 0.24H (the height of the tank), and holing affects the adjacent area with 2D (the diameter of the manhole).
