A three dimensional finite element method is developed in order to analyze multidimensional phase distribution phenomena and the turbulent structure of fully developed turbulent two phase flow. The physical model is based on a two fluid model of two phase flow and the calculated results are compared with against available experimental data. It can predict phase distribution, and velocity distribution including wall and core peaking phenomena in fully developed two phase flow in variety of ducts. Sensitivity studies for the several parameters are performed through numerical experiments using developed method. The developed program makes it possible to analyze phase distribution phenomena in a circular tube, which was impossible for the state-of-arts computer code. Also application will be made for the variety of ducts such as nuclear reactor fuel rod bundles.