Abstract: In China, there are fewer studies on tensioning of prestressed concrete outer wall of large LNG tank. In this paper, theoretical analysis and numerical calculation are combined to derive the tank wall deflection equation for tensioning stage, longitudinal wall bending moment calculation formula, wall bending stress calculation formula and wall hoop stress formula. Then, a finite element model for outer wall of LNG tank is established with ADINA software, and it is used to analyze the stress and displacement of outer wall under different tensioning scenarios. The results show that the bottom concrete of the tank is in bidirectional tensile condition in the prestressed tensioning stage, with the tensile stress close to the tensile strength of concrete, making the bottom as the most dangerous part. The preferred tensioning sequence is: vertically prestressed reinforcement, and then circumferentially prestressed reinforcement (which is tensioned sequentially from top to bottom). The results can provide technical support to the construction of LNG tanks.