Abstract: Considering the shear deformation, a circular water tank was treated as a thick shell, and the differential equation was derived, which was the same as the interactive equation of a Timoshenko beam on a Winkler foundation. When the shear stiffness of tank wall tended to infinite, corresponding equations of thick shell theory can be degenerated into that of thin shell theory. Using the initial parameter method, the solutions to the circular water tank were resolved and the transfer matrix method was established. A two stepped circular water tank with clamped bottom and free top under a triangular distributing load and a radial load was analyzed to demonstrate the shear deformation effect; the transverse deformation, rotating angle, shear force and bending moment were presented to describe the changing with the tank height. Results of thin shell theory, thick shell theory and Ansys software were compared. Numerical analyses indicate that shear deformation leads to small results and thin shell theory used at present is safe. Shear deformation affects the bending moment and shear force more than the loop force and radial displacement. The initial parameter solutions and the transfer matrix method enrich the computing theories of a circular water tank and a Timoshenko beam on a Winkler foundation.