The stress concentration behaviour of internally ring stiffened tubular T and Y joints in offshore platforms is analysed by semi-analytical variational method in this paper. The relation between SCF and geometric parameters of the joint as well as the effect of dimension and location of the ring stiffeners are discussed. A program based on this method is compiled. The stress concentration behavior of internally ring stiffened tubular T and Y joints in offshore platforms is analysed by semi-analytical variational method in this paper. The relation between SCF and geometric parameters of the joint as well as the effect of dimension and location of the ring stiffeners are discussed. A program based on this method is compiled.