Abstract: The outer tank of large-scale LNG tank is used to resist external impacts that may occur to the tank and collect accidental LNG leakage from the inner tank. In order to keep up the gas tightness, liquid tightness and strength of pre-stressed concrete outer tank to make a reasonable tensioning plans for pre-stressed tendons so as to reduce the risk of tensioning failure of pre-stressed tendons, this paper establishes a model for outer tank concrete and pre-stressed tendons with ANSYS software and analyzes the stress and deformation law of concrete outer tank for 4 different pre-stressed tendon tensioning plans based on a 16×10⁴ m³ LNG storage tank. The numerical results show that the maximum deformations of concrete outer tank for the four tensioning plans are basically the same, the maximum deformation will produce after the tensioning of horizontal pre-stressed tendons is finished, and this max deformation is mainly a radial deformation. The deformation development is relatively slow for Plan III. It is suggested that vertical pre-stressed tendons should be tensioned first and then horizontal pre-stressed tendons to avoid additional internal forces on outer tanks in site tensioning construction operation.