Abstract: The outer tank of LNG storage tank is mainly composed of the prestressed concrete, and as a kind of complex nonlinear material, the concrete's load feature is compressive and no-tensile. LNG tanks is a typical kind of pressure vessel, especially the large-scale LNG tanks. The research on stress distribution and crack development of concrete outer tank is of significance. With the finite element software ADINA, the separated model of reinforced concrete is established. With the stress cloud picture and crack development figure, under the conditions of LNG storage tank in the normal running and total leakage state, the research on the stress distribution of the prestressed concrete, crack development situation and its failure pattern is carried out. The result shows that the first principal stress at the two fixed ends is the largest in normal running condition, the first principal stress at a quarter height distance from the bottom is the largest in total leakage state of inner tank, and the three locations are the most vulnerable to crack, and their failure pattern is concrete tensile failure. The result provides a theoretical basis for independent design and construction of domestic LNG tank.