Abstract: This paper studies the joint flexibility on offshore jacket platform， to figure out its effect on structure internal forces and deflection， which results in changes of stiffness and strength of members. By application of three classic joint flexibility theory and rigid theory on typical jacket platform in the South China Sea， the result of structural strength， fatigue life and ultimate strength have been compared. It comes to the general conclusion on influences of tubular joint flexibility on jacket structure.

Key words: jacket platform, tubular joint, joint flexibility, punching shear, ultimate strength