Abstract: The strapping and correction methods for pressurized spherical tank are introduced. The author considers that the variation of tank volume is related to operating pressure and atmospheric temperature. The correction on pressure and temperature must be carried out when tank volume is calculated and atmospheric temperature must be taken as an fiducial temperature when temperature is corrected. If the variation of operation pressure of spherical tank is negligible in one year, the mean operation pressure must be taken to calculate the increment of volume. The influence of pressure and temperature can be taken into an overall consideration when strapping table is made.